Abstracts

Jahrestagung der Arbeitsgemeinschaft Stabile Isotope e. V.

15. – 17. Oktober 2014München

III

Inhaltsverzeichnis Wissenschaftliches Programm Mittwoch, 15. Oktober 2014 IV Donnerstag, 16. Oktober 2014 V Freitag, 17. Oktober 2014 VI

Organisation VII

Vorträge (V) 1

Session 1 – Analytik: Neue Methoden und Techniken 1

Session 2 – Hydrologie und Hydrogeologie 6

Session 3 – Metabolismus und Physiologie 12

Session 4 – Geochemische Stoffkreisläufe und Schadstoffdynamik 21

Session 5 – Klimaänderungen und -rekonstruktionen 27

Session 6 – Ökosysteme 34

Poster (P) 41

Session 1 – Analytik: Neue Methoden und Techniken 41

Session 2 – Hydrologie und Hydrogeologie 56

Session 3 – Metabolismus und Physiologie 68

Session 4 – Geochemische Stoffkreisläufe und Schadstoffdynamik 79

Session 5 – Klimaänderungen und -rekonstruktionen 87

Session 6 – Ökosysteme 91

Index der Autoren X

IV

Wissenschaftliches Programm – Mittwoch, 15. Oktober 2014

1300

Begrüßung 13

20–15

20 Session 1- Neue Methoden und Techniken

1320

High resolution multi-collector gas source isotope ratio MassSpectrometry High Reso- V 1 lution Multi-Collector Gas Source

Hilkert (Thermo Fisher Scientific GmbH, Bremen)

1340

Comparison of methods to determine triple oxygen isotope composition of N2O by V 2 conversion to O2: Introduction of foreign oxygen and sensitivity J. Dyckmann (GWDG, Göttingen)

14

00 N2O isotopic fractionation method to quantify N2O reduction to N2 – a validation in

V 3 He+O2 atmosphere D. Lewicka-Szczebak (Thünen-Institut, Braunschweig) 14

20 Novel tool for simultaneous carbon and nitrogen stable isotope analyses in aqueous

V 4 samples E. Federherr (Elementar Analysensysteme GmbH, Hanau) 14

40 Selenium stable isotope variations as a process tracer in plants - chances and chal

V 5 lenges H. Banning (KIT, Karlsruhe) 15

00 Synthesis and Evaluation of Molecularly-Imprinted Polymers for Compound-Specific

V 6 Isotope Analysis of Polar Organic Micropollutants R. Bakkour (EAWAG, Zürich) 15

20 Kaffeepause

15

50–17

30 Session 2 – Hydrologie und Hydrogeologie

1550

Carbon Isotope signatures of DIC in temperate tidal areas of the southern North Sea V 7 trace submarine groundwater discharge and advective pore water efflux V. Winde (IOW, Rostock) 16

10 Artificial deuterium labeling for a quantification of groundwater recharge in semi-arid -

V 8 regions M. Beyer (BGR, Hannover) 16

30 Hydro-chemical and isotope studies along the Caleque-Oshakati water carrier system:

V 9 possible indicators of anthropogenic influence in the semiarid, densely populated area of Northern Namibia

P. Koeniger (BGR, Hannover) 16

50 Regional nitrogen dynamics in the Bode river system, Germany, as constained by

V 10 stable isotope patterns C. Müller (UFZ, Halle)

1710

Oberirdische Wasseraufnahme der Buche (Fagus sylvatica) in Abhängigkeit von Tro- V 11 ckenstress T. Gebhardt (Universität Göttingen) 17

30–19

00 Postersession I (siehe S. 41 ff.)

ab 20

00 User Meeting Thermo Fisher Scientific GmbH (Paulaner Bräuhaus, Kapuzinerplatz 5)

V

Wissenschaftliches Programm – Donnerstag, 16. Oktober 2014

08

30–10

20 Session 3 – Metabolismus und Physiologie

0830

Keynote-Presentation: Stable isotope profiling under complex conditions V 12 W. Eisenreich (TU München) 09

00 Compound-specific labelling traces metabolic carbon allocation into plant volatile or-

V 13 ganic compounds and CO2 C. Werner (Universität Bayreuth) 09

20 What determines δ

13CO2 during light enhanced dark respiration (LEDR)?

V 14 M. Lehmann (Paul-Scherer-Institut, Villingen) 09

40 αStable carbon isotope fractionation in human steroid metabolism

V 15 U. Flenker (Deutsche Sporthochschule Köln) 10

00 Abiotic methanogenesis from organosulfur compounds under ambient conditions and

V 16 its potential implications for methane formation in eukaryotes F. Keppler (Universität Heidelberg) 10

20 Kaffeepause

1050

Keynote-Presentation: Online methods for the position specific analysis of 13

C in V 17 some light organic compounds N. Yoshida (Tokyo Institute of Technology, Tokyo) 11

20 N2O production pathways in a partial nitritation-anammox reactor: Isotopic evidence

V 18 for N2O production associated with anaerobic NH4+ oxidation?

E. Harris (Empa, Dübendorf) 11

40 Elementkonzentrations- und Isotopenverhältnisbestimmungen an menschlichen Haar-

V 19 strähnen mittels induktiv gekoppeltes Plasma-Massenspektrometrie (ICP-MS) und Iso-topenverhältnis-Massenspektrometrie (IRMS)

N. Scheid (Bundeskriminalamt, Wiesbaden)

1155

Global spatial distribution of natural stable carbon and nitrogen isotope ratios in mo- V 20 dern humans F. Hülsemann (Deutsche Sporthochschule Köln) 12

10 Mittagspause

1300

–1430

Postersession II (siehe S. 41 ff.) 14

30 Kaffeepause

15

00–16

50 Session 4 – Geochemische Stoffkreisläufe und Schadstoffdynamik

1500

Calibration of (13

C/12

C and 2H/

1H)-isotope ratios in methane

V 21 W. A. Brand (MPI, Jena) 15

20 Kann die Sauerstoffisotopensignatur in N2O zur Bestimmung des pilzlichen Anteils an

V 22 der Denitrifikation genutzt werden? L. Rohe (Thünen-Institut, Braunschweig/Göttingen) 15

40 δD and δ

13C measurements of chloromethane from terrestrial and extraterrestrial ma-

V 23 tter and its implications for the search of organic matter on Mars M. Greule (Universität Heidelberg, Heidelberg) 16

00 Carbon, nitrogen, and hydrogen isotope analysis of N-Nitrosodimethylamine (NDMA)

V 24 formed during chloramination of Ranitidine-containing waters S. Spahr (EAWAG, Dübendorf)

VI

1620

Application of compound-specific stable isotope analysis for source identification of V 25 chlorinated organic pollutants N. Ivdra (UFZ/Isodetect GmbH, Leipzig) 16

35 Forensische Nutzung der IRMS: Profiling von „Crystal Meth“

V 26 S. Schneiders (Bundeskriminalamt, Wiesbaden) 17

00 ASI-Mitgliedertreffen

20

00 Konferenz-Abendessen (Hofbräuhaus, Am Platzl 9)

Wissenschaftliches Programm – Freitag, 17. Oktober 2014

0830

–1000

Session 5 – Klimatologie und Klimarekonstruktionen 08

30 Which climate factor does best explain carbon isotope variations in tree-rings: tempe-

V 27 rature, precipitation or sunshine duration? M. Saurer (Paul-Scherer-Institut, Villingen) 08

50 Die Mischung macht’s!? Facilitation zwischen adulten Buchen und Fichten im Tro-

V 28 ckenstress T. Grams (TU-München) 09

10 Revisiting Mt. Kilimanjaro - reinterpreting δ

2H results of n-alkane biomarkers

V 29 M. Zech (Universität Bayreuth) 09

30 Reconstructing lake evaporation history and the isotopic composition of precipitation

V 30 by a coupled δ18

O-δ2H biomarker approach

J. Hepp (Universität Bayreuth/Halle) 09

50 Verleihung des Isotopenpreises

V 31 D. Sachse (Universität Potsdam) 10

30 Kaffeepause

10

50–12

50 Session 6 – Ökosysteme

1050

Geographical patterns in the isotopic ecology of wool, past and present V 32 I. von Holstein (Universität Kiel) 11

10 It's complex: Using

13C/

15N plant and soil isoscapes to capture environmental gradi-

V 33 ents, land-management effects and land-use patterns across a NE German agricultur-al landscape

K. Nitzsche (ZALF, München)

1130

Light limitation stimulates partial mycoheterothrophy in rhizoctonia-associated orchids V 34 J. Schiebold (Universität Bayreuth) 11

50 Intramolecular isotope distributions detect CO2-driven increases in photosynthesis

V 35 over centuries I. Ehlers (Universität Umeå) 12

10 Investigations of (soil) respiration in a long-term Free Air CO2 Enrichment (FACE)

V 36 experiment K. Lenhart (Universität Gießen) 12

30 Using stable oxygen isotopes to assess vegetation impact on ecosystem water cycle

V 37 and productivity in a Mediterranean oak woodland M. Dubbert (Universität Bayreuth) 12

50–13

15 Preisverleihungen und Schlussworte

1315

–1445

Laborführung

VII

Organisation

Wissenschaftliches Organisationskomitee Barth, Prof. Dr. Johannes Universität Erlangen-Nürnberg Brandt, Prof. Dr.Willi MPI, Jena Einsiedl, Prof. Dr. Florian TU München Eisenreich, Prof. Dr. Wolfgang TU München Gehre, Dr. Matthias UFZ, Leipzig Gebauer , Prof. Dr. Gerhard Universität Bayreuth Mayr, Dr. Christoph LMU München Schnitzler, Prof. Dr. Jörg Helmholtz Zentrum München Schnyder, Prof. Dr. Hans TU München Siegwolf, Prof. Dr. Rolf PSI, Villingen von Geldern, Dr. Robert Universität Erlangen-Nürnberg Elsner, Dr. Martin Helmholtz Zentrum München Stumpp, Dr. Christine Helmholtz Zentrum München Meyer, Dr. Armin Helmholtz Zentrum München Lokale Organisation

Insititut für Grundwasserökologie und Abteilung Kommunikation des Helmholtz Zentrum Münchens-Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH) sowie die Conventus Congressmanagement & Marketing GmbH

Elsner, Dr. Martin Institut für Grundwasserökologie, Helmholtz Zentrum München Stumpp, Dr. Christine Institut für Grundwasserökologie, Helmholtz Zentrum München Meyer, Dr. Armin Institut für Grundwasserökologie, Helmholtz Zentrum München Nehmeyer, Petra Abteilung Kommunikation, Helmholtz Zentrum München Kuchler, Marion Abteilung Kommunikation, Helmholtz Zentrum München Caune, Nora Conventus Congressmanagement & Marketing GmbH Al-Hamadi, Nadia Conventus Congressmanagement & Marketing GmbH

VIII

Wir danken folgenden Firmen sehr herzlich für Ihre großzügige Unterstützung:

Axel Semrau GmbH & Co.KG

Campro Scientific GmbH

Delta Analytics OHG

Elementar Analysensysteme GmbH

HEKAtech GmbH

IVA-Analysentechnik GmbH & Co. KG

Thermo Fisher Scientific GmbH

UGT GmbH

IX

1

Vorträge

Session 1 – Analytik: Neue Methoden und Techniken

V 1 High Resolution Multi-Collector Gas Source Isotope Ratio MassSpectrometry High Resolution Multi-Collector Gas Source

A. Hilkert1, M. Deerberg

1, H.- J. Schlüter

1, J. Schwieters

1

1Thermo Fisher Scientific (Bremen) GmbH, Bremen, Deutschland

Gas isotope ratio mass spectrometry is based on the conversion of complex molecules into simple gases like H2, N2 and CO2 to allow high precision determination their isotope ratios. In most applica-tions position-specific and clumped isotope information is lost. Hence the direct application of target molecules into the IRMS would be required with the consequence of more complex mass spectra and an increase of isobaric interferences on low abundant isotopologues being targeted in such applica-tions. Medium or high mass resolution is the method of choice for accurate quantification of low abun-dant ion beams resolving them from isotopologues, contaminants and adducts with the same nominal mass. The MAT 253 Ultra - a high resolution double-focusing isotope ratio mass spectrometer, which has been installed in the Caltech laboratories for stable isotope geochemistry in Dec. 2011. This instru-ment achieves mass resolving power of up to 26000 (M/�M, 5%, 95 % definition) and can analyze di-verse gases and semi-volatile compounds by dual inlet and continuous flow sample introduction. It has a multicollector array with 7 detector positions. 6 of the collectors can be moved automatically to ar-range for the simultaneous acquisition of the required masses in complex isotopologue systems. Ions can be registered through SEM or faraday collectors, spanning up to a 1013 range in signal strength. Abundance sensitivity is as good as 10-12, and precisions are commonly counting statistics limited down to levels of 0.01 ‰ (or better) for a wide range of species.

The MAT 253 Ultra enables many previously impossible isotopic analyses of gases and volatile organ-ics and their fragment and adduct ions, such as: δ13C, δD and 13CH3D of methane; δ13C of propane and many of its fragments (enabling position-specific 13C determination); direct analysis of δ17O δ18O, δ15N and 15N-18O ‘clumping’ in N2O and its NO fragment and clumped isotope analysis of CO2 free of contaminant isobaric interferences.

We are presenting an update on our concepts and recent work on the MAT 253 Ultra high resolution double focusing IRMS. Recent applications performed on the MAT 253 Ultra prototype will be present-ed in cooperation with John Eiler et al., California Institute of Technology, Pasadena, CA.

2

V 2 Comparison of methods to determine triple oxygen isotope composition of N2O by conversion to O2: Introduction of foreign oxygen and sensitivity

J. Dyckmans1, R. Langel

1, D. Lewicka-Szczebak

2, L. Szwec

1, R. Well

2

1Universität Göttingen, Kompetenzzentrum Stabile Isotope, Göttingen, Deutschland

2Thünen Institute, Climate-Smart Agriculture, Braunschweig, Deutschland

The Δ17

O (or 17

O anomaly), i.e. the deviation of the 18

O/16

O to 17

O/16

O ratio from “normal” mass de-pendent fractionation can be used as an oxygen tracer that is not affected by fractionation processes (as mass dependent fractionation will preserve the Δ

17O of the oxygen). However, in molecules like

N2O, the Δ17

O cannot be determined, as variations in the 15

N/14

N ratio will affect the 17

O signal. There-fore, N2O must be converted to O2 before Δ

17O may be measured.

There are different approaches published for the conversion of N2O to O2: thermal decomposition in a hot gold oven (Kaiser et al. 2007, Smirnoff et al. 2012) and microwave discharge (Mukotaka et al. 2013). Here we report results on the comparison of the approaches of Mukotaka et al. and Smirnoff et al. with regard to signal attenuation by introduction of foreign oxygen and sensitivity of the methods.

References

J. Kaiser, M.G. Hastings, B.Z. Houlton, T. Röckmann, D. M. Sigman (2007) Triple oxygen isotope analysis of nitrate using the denitrifier method and thermal decomposition of N2O. Anal. Chem. 79, 599-607. A. Mukotaka, S. Toyoda, N. Yoshida, R. Well (2013) On-line triple oxygen isotope analysis of nitrous oxid using decomposition by microwave discharge. Rapid Communications in Mass Spectrometry 27, 2391-2398 A. Smirnoff, M.M. Savard, R. Vet, M.C. Simard (2012) Nitrogen and triple oxygen isotope in near-road air samples using chemical conversion and thermal decomposition. Rapid Communications in Mass Spectrometry 26, 2791-2804

3

V 3 N2O isotopic fractionation method to quantify N2O reduction to N2 - a validation in He+O2 atmosphere

D. Lewicka-Szczebak1, J. Augustin

2, A. Giesemann

1, R. Well

1

1Thünen Institut für Agrarklimaschutz, Braunschweig, Deutschland

2Leibniz-Zentrum für Agrarlandschaftsforschung, Müncheberg, Deutschland

Quantifying denitrification in arable soils is crucial in predicting nitrogen fertiliser losses and N2O emis-sions, but very challenging, because the final product, N2, cannot be measured directly due to high atmospheric background. Stable isotopocule analyses of residual N2O (d

15N, d

18O and SP =

15N site

preference within the linear N2O molecule) may be useful in determination of the N2O reduction pro-gress, but the knowledge on the associated isotopic fractionation mechanisms must be improved. Until now the isotopic fractionation factors (η) during N2O reduction have been determined in anoxic exper-iments showing large range of values for η

18O and η

15N but quite robust vales for ηSP [1]. Hence, SP

values of residual N2O can serve as a potential tool to quantify N2O reduction.

But are the fractionation factors from artificially regulated experiments transferable to natural field con-ditions? There is still a gap between the targeted laboratory incubations and field applications, namely, the experimental approaches are missing, where in conditions mostly similar to real soil conditions, fractionation factors are confirmed or refined. Here we present the first laboratory study for validation of isotopic fractionation factors associated with N2O reduction under oxic atmosphere. We applied an enhanced experimental approach allowing for the simultaneous N2O production and reduction within the same soil incubation vessel [1] and performed incubations in He or He/O2 atmosphere where N2 and N2O fluxes were measured directly [2].

The results from arable silt loam soil incubation will be presented. The ηSP values determined by pre-vious anoxic experiments have been confirmed for oxic atmosphere. But interestingly, the correlations between SP and d

15N or d

18O values are significantly different for oxic and anoxic atmosphere, where-

as the correlations between d15

N and d18

O values are independent on oxygen abundance. This is probably the effect of N2O diffusion from the soil matrix, which has an impact on d

15N and d

18O but not

on SP values of N2O. The denitrification product ratios (N2O/(N2+N2O)) were calculated based on measured SP values and compared to the true product ratios measured directly. The results of these calculations are very sensitive to the accepted values for initial SP of produced N2O and isotopic frac-tionation factor. If values determined in this experiment (oxic, dynamic) are used, the calculated prod-uct ratio is very consistent with the measured one (mean error 10%), but if values determined for this soil in previous experiments (anoxic, static) are used, large discrepancy is observed (mean error 40%). Hence, the exact determination of initial SP of produced N2O and isotopic fractionation factor for particular conditions is crucial for proper application of this method.

References

[1] Lewicka-Szczebak, et al. (2014), Geochim Cosmochim Ac, 134, 55-73. [2] Eickenscheidt, T et al. (2014) Biogeosciences, 11, 2961-2976.

4

V 4 Novel tool for simultaneous carbon and nitrogen stable isotope analyses in aqueous samples

E. Federherr1,2

, F. Volders1, C. Cerli

3, K. Kalbitz

3, T. Schmidt

2, H. J. Kupka

1, L. Lange

1, R. Dunsbach

1,

R. Panetta4

1Elementar Analysensysteme GmbH, Hanau, Deutschland

2University of Duisburg-Essen, Instrumental Analytical Chemistry, Essen, Deutschland

3University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics, Amsterdam,

Niederlande 4Isoprime Ltd, Manchester, Großbritannien

Investigation of transformation and transport processes of carbon and nitrogen in ecosystems plays an important role to understand and predict their dynamics and role in biogeochemistry. Consequently, suitable and accurate methods for concentration as well as stable isotopic composition analysis of carbon and nitrogen in waters and aqueous solutions play a significant role.

Traditionally dissolved carbon and nitrogen stable isotope analysis (SIA) is performed using either of-fline sample preparation followed by elemental analysis isotope ratio mass spectrometry (EA/IRMS) or modified wet chemical oxidation based device coupled to IRMS. Recently we presented a high tem-perature combustion system (HTC), which significantly improves upon these methods for dissolved organic carbon (DOC) SIA.

The analysis of δ15

N of dissolved nitrogen still has large limitations. Its low concentration makes EA/IRMS laborious, time and sample consuming. Systems based on wet chemical oxidation-IRMS bare the risk of sensitivity loss as well as of fractionation due to incomplete mineralization. In addition, the high solubility of molecular nitrogen in water remains a technical challenge, as it requires additional separation steps to distinguish between physically dissolved nitrogen and bound nitrogen.

Further development of our HTC system lead to the implementation of the δ15

N determination which now coupled, into a novel total organic carbon (TOC) analyzing system, especially designed for SIA of both, carbon and nitrogen. Integrated, innovative purge and trap technique (peak focusing) for nitro-gen with aluminosilicate adsorber and peltier element based cooling system, in combination with high injection volume (up to 3 mL) as well as favorable carrier gas flow significantly improves sensitivity. Down to 1ppm and less total nitrogen can be measured with precision of ≤ 0.5‰. To lower the back-ground caused by physically dissolved nitrogen new, membrane-vacuum based, degasser was de-signed for online separation of physically dissolved nitrogen.

This novel HTC system, “iso TOC cube”, provides an innovative tool with large potential in investiga-tion of biogeochemical carbon and nitrogen cycles.

Anhang 1

5

V 5 Selenium stable isotope variations as a process tracer in plants - chances and challenges

H. Banning1, M. Stelling

1, N. Alexandra

1, E. Eiche

1, T. Neumann

1, R. Schönberg

2, R. Brendel

3,

P. Nick3, M. Riemann

3

1KIT, Institute of Mineralogy and Geochemistry, Karlsruhe, Deutschland

2University of Tübingen, Department of Geosciences, Tübingen, Deutschland

3KIT, Botanical Institute, Karlsruhe, Deutschland

Selenium (Se) is an essential and toxic trace element with a narrow tolerance range for plants, ani-mals and humans. The Se uptake and metabolism of plants is a key factor for Se accumulation in the environment and Se supply within the food chain. According to various studies (e.g. [1]) the determina-tion of stable Se isotope fractionation is a powerful tool for the exploration of environmental processes with high fractionation at reduction and significant fractionation at enzymatic transformation reactions. Therefore it is promising also for the detection of plant related Se cycling. We are investigating in how far Se transport and transformation processes in plants induce stable Se isotope fractionation and if reconstruction of metabolic processes using isotope patterns is possible.

Based on previous studies (e.g. [2]) showing the variation of Se pathways with source Se species, we perform systematic plant cultivation experiments in a minimum parameter set up, separately exposing selenate (SeO4

2-), selenite (SeO3

2-) and selenomethionine (Seorg) in different concentrations. We ob-

serve uptake and translocation patterns strongly varying with Se species and concentration. This indi-cates the presence of rate limiting steps as well as the dependence of reaction and transport pathways based on Se related conditions. These are prerequisites for the reasonable use of Se isotope signa-tures to detect individual processes.

The accurate measurement of stable Se isotope ratios as well as the preparation and purification of plant material meeting the demands of the analytics is quite challenging. We use a multi-collector in-ductively coupled plasma mass spectrometer with on-line hydride generation and additional methane injection. Both measures increase the plasma temperature, stabilize the Se signal, and highly reduce isobaric interferences. For the correction of artificial fractionation due to sample preparation and in-strumental mass bias we use the double spike technique ([3]), which requires the complete destruction of organic Se compounds during digestion. As the common plant microwave digestion method was proved to be insufficient for our purposes we set up an alternative one based on [4], which allows the use of lower acid amounts, reduces the blanks and memory effects and significantly increases the effi-ciency of organic destruction ([5]).

Precise and accurate Se isotope determinations require the removal of potential interferences in the sample matrix. For purification of samples with plant matrices we tested two methods based on flow through columns packed with different materials previously described for inorganic sediments [6] and bacterial samples [7]. We chose our preferential method with regard to Se yield, residual matrix ele-ments and matrix effects during isotope measurements.

References

[1] Johnson, T.M. & Bullen, T.D. (2003). Chemical Geology 204: 201- 214. [2] Li, H.-F., McGrath, S.P., Zhao, F.-J. (2008). New Phytologist 178: 92-102. [3] Zhu, J.-M., Johnson, T.M., Clark, S.K. & Zhu, X.-K. (2008). Chin. J. Anal. Chem., 36(10): 1385-1390. [4] Kopp, G. (1999): E900 - MLS Applikation Aufschluss: Se. MLS GmbH - application lab, Leutkirch, Germany. [5] Wasilewska, M., Goessler, W., Zischka, M., Maichin, B. and Knapp, G. (2002). J. Anal. At. Spectrom. 17: 1121-1125. [6] Elwaer, N. and Hintelmann, H. (2008). J. Anal. At. Spectrom. 23: 733-743. [7] Ellis, A.S., Johnson, T.M., Herbel, M.J., Bullen, T.D (2003). Chemical Geology 195: 119-129.

6

Vorträge

Session 2 – Hydrologie und Hydrogeologie

V 6 Synthesis and Evaluation of Molecularly-Imprinted Polymers for Compound-Specific Isotope Analysis of Polar Organic Micropollutants

R. Bakkour1,2

, T. Hofstetter1,2

1ETH, Institute of Biogeochemistry & Pollutant Dynamics, Zurich, Schweiz

2Eawag, Environmental Chemistry, Dübendorf, Schweiz

Polar organic micropollutants, such as pesticides, pharmaceuticals and consumer chemicals, are fre-quently detected in aquatic environments and hence are a major concern to the environment and hu-man health. Compound-specific isotope analysis (CSIA) is a promising tool for assessing sources and transformation processes of polar organic micropollutants in aquatic environments. There are, howev-er, two major challenges: (1) Polar organic micropollutants occur at very low levels and, as a conse-quence, large amounts of water are required to achieve analyte enrichment with factors exceeding 50’000, inevitably leading to large interferences from the matrix. (2) The polarity of these micropollutants impedes the use of typical non-polar sorbates for solid-phase enrichment without fur-ther cleanup steps. In view of these challenges, the use of molecularly imprinted polymers (MIP) is a promising approach to selectively retain polar organic micropollutants with reduced matrix interfer-ences. In this work, we explore the use of MIP to selectively retain 1H-benzotriazole, a frequently found complexing agent used in dishwashing detergents and an important representative of polar aquatic micropollutants.

MIPs were synthesized in the presence of 1H-benzotriazole or similar analogous molecule as a tem-plate, which leaves cavities in the polymer matrix with a specific affinity to the template and closely re-lated structures. After extraction of the template, specific recognition of substituted benzotriazoles and other compounds was tested in chromatographic columns packed with either the imprinted polymer (MIP) or the non-imprinted polymer (NIP). In addition, CSIA measurements of carbon and nitrogen were carried out for river water extracts before and after clean-up by the synthesized polymers.

Imprinting of benzotriazole molecule with factors larger than 1.0 was successfully achieved. No selec-tivity was observed for few other tested compounds with the exception of s-chloro-triazines (e.g. atra-zine). Comparison of CSIA measurements before and after the selective cleanup indicates that no iso-topic fractionation occurs on carbon during the process of loading the imprinted polymers with excess of 1H-benzotriazole. However, isotopic fractionation on nitrogen is induced if the recoveries are not complete. The ability of MIP to selectively suppress the matrix, in contrast to NIP, is demonstrated in the cleanup test of river water extracts.

This approach will enable us to enrich and clean large amounts of aqueous samples while minimizing interferences from organic matter and other organic micropollutants in the sample matrix and thus of-fer new perspectives for CSIA of polar organic micropollutants. Anhang 1

7

V 7 Carbon Isotope signatures of DIC in temperate Tidal Areas of the southern North Sea trace Submarine Groundwater Discharge and Advective Pore water efflux

V. Winde1, I. Schmiedinger

1, P. Escher

1, P. Böning

2, A. M. Al-Raei

3, B. Schneider

1, G. Liebezeit

4,

M. E. Böttcher1

1Institut für Ostseeforschung Warnemünde, Marine Geologie, Rostock, Deutschland

2ICBM, Oldenburg, Deutschland

3MPI, Bremen, Deutschland

4ICBM, Wilhelmshaven, Deutschland

We show a synthesis from different projects funded by BMBF, DFG, and IOW (BIOACID, 'BioGeoChemistry of theWaddenSea') dealing with tidal basins of theGermanWaddenSeain particular focusing here on the dissolved carbonate.

It was the aim of this study to investigate seasonal and tidal responses of the pelagic carbonate sys-tem in the basin without and under superimposition by in-situ transformation processes, like primary production and pelagic respiration. Both, the concentration and the stable carbon isotope composition of DIC are shown to be valuable tools to follow and analyze the tidal and spatial variations in the pe-lagic carbonate system of the tidal coastal waters.

The present study combines the sampling campaigns from seasonal, tidal and spatial resolutions that investigated the time and location response of the pelagic carbonate system under different magni-tudes. In addition water samples from fresh water inlets, pore water, and coastal sediments were tak-en at different sites (e.g. Spiekeroog, Jade Bay). Salinity, temperature and pH were immediately measured. Water samples were filtered for stable isotope (δ

13C(DIC)) and element (e.g. major and

trace elements, nutrient, TA, DIC) composition. Finally, direct advective pore water efflux from perme-able sediments during low tide was considered, too.

It has been shown that seasonal and tidal compositional variations occur in the investigation areas that indicate the mixing ofNorth Seawith fresh waters of different sources, superimposed by benthic-pelagic coupling. The combination of both, the concentration and the stable carbon isotope composi-tion of DIC is shown to be valuable tools to follow and interpret the basic processes causing tidal and spatial variations in the pelagic carbonate system of the coastal waters.

An additional source for DIC and TA as well as nutrients and redox-sensitive elements is the benthic-pelagic coupling witch has been shown by outflow of nutrient enriched anoxic pore waters at intertidal sand plates in the back barrier tidal areas of the southern North Sea.

8

V 8 Artificial deuterium labeling for a quantification of groundwater recharge in semi-arid regions

M. Beyer1, M. Gaj

1, P. Koeniger

1, J. Hamutoko

2, H. Wanke

2, C. Lohe

1, T. Himmelsbach

1

1BGR Hannover, B2.3 Grundwasser, Hannover, Deutschland

2University of Namibia, Windhoek, Afrika

Proper estimations of groundwater recharge rates are essential for a sustainable management of wa-ter resources. Numerous methods are available (Scanlon et al., 2002); however, their applicability and reliability varies greatly depending on available data, spatiotemporal scales and climatic conditions within the studied area. The peak-displacement method (Saxena & Dressie, 1984) has been used ex-tensively to estimate groundwater recharge rates in regions, where a distinctive seasonal variation of the stable isotopes oxygen-18 (

18O) and deuterium (

2H) in precipitation is present ( Saxena, 1984;

Adomako et al., 2010) . In semi-arid climates with only one rainy season this prerequisite is eventually not fulfilled; hence this simple and reliable method cannot be applied. In this study we present results of an artificial deuterium labeling experiment(

2H2O, 70%)in order to estimate groundwater recharge

with the peak-shift method and characterize water movement during and after a synthetic rain event.

The study was carried out in the framework of the SASSCAL project in the Cuvelai-Etosha Basin in Northern Namibia. Experiments were carried out at two locations with different soil and vegetation types: A forest site (‘Eenhana’) with deep sandy soil and a shrub-/woodland site (‘Okongo’) character-ized by dark loamy sand underlain by a thick layer of calcrete. At both locations, soils were first satu-rated to trigger typical rainy season conditions and avoid immediate evaporation of the deuterated wa-ter. Subsequently, 500 ml of

2H2O was applied homogenously over a 0.25 m

2 test plot at 25 cm depth.

Finally, a 10 mm artificial rain event was applied onto the plot. Soil samples were collected every 10 cm to a maximum depth of 7.4 m with a hand auger after 1, 2 and 10 days as well as after the rainy season. From these, soil water was extracted in the laboratory and subsequently analyzed for δ

2H

concentrations using a Picarro L2120-i cavity-ringdown (CRD) water vapor analyzer after vaporization and with a Los Gatos DL 100 directly in the field. Gravimetric water content and soil hydraulic proper-ties were determined in the lab.

We found groundwater recharge rates of 9mm at Eenhana and 4mm at the Okongo site for the rainy season 2013/2014. The injected deuterium peaks travelled from 2.3 m to 5.5 m and from 0.5 to 0.9 m, respectively. Extremely high saturated conductivities were found at both sites. Potential for recharge, however, is markedly reduced at Okongo due to presence of the calcrete layer. The study shows that through the injection of

2H2O, the peak-shift method can successfully be applied in semi-arid environ-

ments. Even with small amounts of 2H2O, the tracer peak could be detected after one whole rainy sea-

son. The experiments demonstrate a valuable, hence cheap and reliable, technique to estimate groundwater recharge rates in semi-arid regions and areas with low data availability. Further validation of the method regarding spatial and temporal scales is needed.

Adomako, D., Maloszewski, P., Stumpp, C., Osae, S., & Akiti, T. T. (2010). Estimating groundwater recharge from water isotope (δ 2 H, δ 18 O) depth profiles in the Densu River basin, Ghana. Hydrolog-ical Sciences Journal, 55(8), 1405-1416. Saxena, R. K. (1984). Estimation of groundwater recharge and moisture movement in sandy for-mations by tracing natural oxygen-18 and injected tritium profiles in the unsaturated zone. Nordic Hy-drology, 235-242. Saxena, R. K., & Dressie, Z. (1984). Estimation of groundwater recharge and moisture movement in sandy formations by tracing natural oxygen-18 and injected tritium profiles in the unsaturated zone. In IAEA Symposium (pp. 139-150). Scanlon, B. R., Healy, R. W., & Cook, P. G. (2002). Choosing appropriate techniques for quantifying groundwater recharge.Hydrogeology Journal, 10(1), 18-39.

9

V 9 Hydro-chemical and isotope studies along the Caleque-Oshakati water carrier system: possible indicators of anthropogenic influence in the semiarid, densely populated area of Northern Na-mibia

P. Koeniger1, M. Beyer

1, M. Gaj

1, J. Hamutoko

2, H. Wanke

2, T. Himmelsbach

1

1Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Grundwasserbeschaffenheit,

Ressourcen und Dynamik, Hannover, Deutschland 2University of Namibia (UNAM), Geology Department, Windhoek, Namibia, Afrika

Since 1973 Kunene River water (currently between 47 and 63 Million m³ per year [1]) is carried from the Calueque Dam in Angola along a 150 km concrete canal to Oshakati in the central part of the Cuvelai-Etosha Basin which supplies drinking water to the most densely populated area of Namibia. Backup storage is held in the Olushandja Dam and in water towers at Ogongo, Oshakati and Ondangwa. About 4,000 km of pipeline radiates out from purification schemes and supplies most of the people and the livestock [2,3]. The canal is open along most of its course to Oshakati, allowing livestock and people living nearby to freely make use of the water. During the rainy season, flood wa-ter from the vast Oshana drainage system swashes into the canal bearing a potential health risk when consumed untreated.

Within the SASSCAL project (www.sasscal.org) water samples were collected during field campaigns in November 2013 right before the onset of the rainy season, and in June 2014 after the rainy season. Water samples were collected at 14 sites along the canal for hydro-chemical analyzes and stable wa-ter isotopes (deuterium and oxygen-18). Temperature, electric conductivity, pH-value, and oxygen content were measured in the field. A Picarro L2120-i water vapor analyzer was used for stable iso-tope analyzes with accuracies of 0.2‰ and 0.8‰ for δ

18O and δ

2H, respectively. A discussion of iso-

tope and hydro-chemical evolution of the canal water in comparison to local rain, Kunene source water and available groundwater will be presented in a context of water availability, vulnerability and water resources management.

[1] Directorate of Rural Water Supply (2004): Directorate of Rural Water Supply 1993-2003. Ministry of Agriculture, Water and Rural Development, Windhoek, Namibia, 64 pp. [2] Mendelson J., Jarvis A., Robertson T. (2013): A profile and Atlas of the Cuvelai-Etosha basin. Min-istry of Agriculture, Water and Rural Development, Windhoek, Namibia, 170 pp. [3] Christelis G., Struckmeier W. (Eds) (2001): Groundwater in Namibia - an explanation to the Hydro-geological Map. Department of Water Affairs, Ministry of Agriculture, Water and Rural Development, Windhoek, Namibia, 128 pp. Fig. 1: Stable isotope values of precipitation (small black dots), groundwater (triangles and squares), Kunene River (white circles) and Calueque-Oshakati canal water (grey circles) in the Cuvelai-Etosha Basin (CEB), Northern Namibia. Key words: Hydro-chemistry, stable isotopes, water supply, semiarid Northern Namibia Anhang 1

10

V 10 Regional nitrogen dynamics in the Bode river system, Germany, as constained by stable iso-tope patterns

C. Müller1, R. Krieg

1, R. Merz

1, K. Knöller

1

1Helmholtz-Zentrum für Umweltforschung, UFZ Halle (Saale), Catchment Hydrology, Halle (Saale),

Deutschland

Monitoring concept

We used nitrogen and oxygen isotopic signatures of riverine nitrate of main tributary streams from the Bode River in the Harz Mountains and Boerde region, Germany, to delineate nitrate sources and ni-trogen transformation processes. Between March 2012 and December 2013 we collected monthly wa-ter samples from up to 133 tributary streams several times and determined hydrochemical parameters as well as δ

15N and δ

18O of nitrate. Precipitation and groundwater were sampled and considered as

potential input factors. The catchment in the middle and lowlands is strongly influenced by agricultural land use that occupies an area of 2310 km², which is about 70 % of the overall size of the catchment.

Discussion of Results

Nitrate stemming from different sources such as ammonia (NH4) fertilizer, soil-nitrogen, organic ferti-lizer or precipitation shows in part extremely significant δ

15NNO3 and δ

18ONO3 - differences, which can

be used to characterize and quantify the different source contributions (Kendall and McDonnell, 1998). Generally, we observed a significant regional and partly temporal variation of nitrate isotopic signa-tures throughout the catchment. Stream section within the high mountains contain nitrate in low con-centrations with low δ

15NNO3 values, whereas streams in the lowlands, affected by an increasing hu-

man impact, show a highly regional and seasonal variation in δ15

NNO3 ranging between 1 ‰ and 14 ‰AIR. A clear correlation seems to exist between the percentage of agricultural land use area in the sub-catchments and δ

15NNO3. Streams within catchments with a higher proportion of agricultural land

use show high δ15

NNO3 signatures of about 8 ‰ to 11 ‰AIR during all seasons. The correlation be-tween land use area and d

15NNO3 is superimposed by a season-depending impact of microbial

denitrification. Denitrification, especially evident in the lowlands, predominantly takes place in the riv-erbeds. Beyond that, mixing processes of different nitrate sources and temperature-depending biologi-cal processes such as nitrification have to be taken into consideration.

Regional landscape information like land use, soil, geology, topology and recharge as well as quantita-tive discharge information is combined with the temporal and spatial isotope distribution patterns. The subsequent comprehensive geo-statistical analysis considering stream network topology by using the topological kriging method (Skøien et al., 2006) enables the recognition of dominant hydrological and microbiological processes and of hot spots of anthropogenic impacts. This information may be used for parameterization and validation of regional scale hydrological and matter flux models.

Kendall, C., McDonnell, J. J. E. (1998): Tracing Nitrogen Sources and Cycling in Catchments.Isotope Tracers in Catchment Hydrology(Elsevier Science B.V., Amsterdam): 55.

Skøien, J. O., Merz, R., Blöschl G. (2006): Top-kriging - geostatistics on stream networks.Hydrology and Earth System Sciences10: 277-287.

11

V 11 Oberirdische Wasseraufnahme der Buche (Fagus sylvatica) in Abhängigkeit von Trockenstress

T. Gebhardt1, T. Grams

2, R. Matyssek

2, S. Magin

2

1Georg-August-Universität Göttingen, Waldbau und Waldökologie der gemäßigten Zonen, Göttingen,

Deutschland 2Technische Universität München, Ökophysiologie der Pflanzen, Freising, Deutschland

Der Waldumbau von Fichtenreinbestanden (Picea abies [L.] Karst) in Mischwalder, v.a. durch die Einbringung der Buche (Fagus sylvatica), ist in Anbetracht des voranschreitenden Klimawandels und der prognostizierten Zunahme von Trockenheitsperioden während der Sommermonate in Deutschland in vollem Gange. Aus diesem Grund gewinnt vor allem die Erforschung des Wasserhaushaltes und der Trockenstresstoleranz von Waldbestanden und deren Baumarten an Bedeutung. Bei der Beurteilung der Trockenstresstoleranz verschiedener Bau-marten, konnte deren Kapazitat zur Wasseraufnahme bei Regenereignissen über die oberirdischen Organe (Blatt und Spross) eine bisher unterschätzte Rolle spielen. Aus diesem Grund wurde anhand eines Klimakammerexperimentes mit Hilfe von Deuterium gelabeltem Wasser überprüft, ob junge Bu-chen zu einer oberirdischen Wasseraufnahme befähigt sind. Im Fokus standen die Fragen, inwieweit die aufgenommene Wassermenge von der Trockenstressdosis abhängig ist und über welche Pflan-zenteile dieses Wasser aufgenommen wird. Hierzu wurden die jungen Buchen drei Trockenheitsstufen ("trocken•", "halbtrocken•" und "feucht•") ausgesetzt und der Trockenstress mittels pre-dawn Was-serpotential, der stomatären Leitfähigkeit und der Photosyntheserate quantifiziert. Alle drei Größen zeigten ein deutliches Absinken mit zunehmender Trockenheit des Bodens. Die Hälfte der Pflanzen einer Trockenstufe wurde als Kontrolle verwendet. Die oberirdische Biomasse der anderen Hälfte wurde zwei Mal im Abstand von 1,5 Stunden fur 5 Sekunden in mit Deuterium gelabeltes Wasser ge-taucht. Die Töpfe und die unteren Sprossabschnitte waren dabei sorgfaltig abgedichtet, so dass kein Wasser in den Boden gelangen konnte. Des Weiteren wurden die Kontroll- und Labelpflanzen zusatzlich in Plastiktuten gehüllt, um die Transpiration zu unterdrücken. Nach einer Zeitspanne von 3 Stunden wurde erneut das Wasserpotential gemessen und Xylemproben der befeuchteten und unbefeuchteten Pflanzenteile sowie Wurzelproben entnommen. Die Proben wurden anschliesend kryodestilliert und auf ihren Deuteriumgehalt untersucht. Die Ergebnisse zeigten einen Anstieg des Wasserpotentiales über den Wert des pre-dawn Wasserpotentiales für die Gruppen "feucht•" und "halbtrocken•" und einen signifikant höheren Deuteriumgehalt in allen gelabelten Pflanzen im Ver-gleich zu den Kontrollen. Ebenfalls zeigte sich ein deutlich erhöhter Deuteriumgehalt im Xylem bis in den unteren Spross und die Wurzeln. Somit konnte sowohl die Möglichkeit zur oberirdischen Aufnahme von Wasser als auch ein deszendenter Fluss bei der Buche nachgewiesen werden.

12

Vorträge

Session 3 – Metabolismus und Physiologie

V 12 Stable isotope profiling of metabolism under complex conditions

W. Eisenreich1

1Technische Universität München, Lehrstuhl für Biochemie, Garching, Deutschland

A powerful method to analyze metabolism under complex and physiological conditions is based on in-corporation experiments using

13C-labeled substrates.

13C-Enrichments and positional isotope distribu-

tions in multiple metabolic products are analyzed by GC/MS and /or NMR spectroscopy providing de-tailed quantitative information about substrate usage, metabolic pathways and fluxes as well as the impacts of environmental factors upon these processes. In the meantime, the experimental-driven and model-free approach has provided crucial data about relative metabolic fluxes and adaptation in many bacterial pathogens also under intracellular growth. Using this method, biosynthetic pathways of isoprenoids could also be unraveled in whole plants under physiological conditions. Some examples will be presented showing the power and the limits of the method.

Multiple carbon usage including glucose, glucose-phosphate, glycerol and amino acids has been shown for intracellular Listeria monocytogenes and Legionella pneumophila in response to the specific conditions of various host cells. This documents the metabolic strategies of intracellular pathogens for efficient survival and replication. Indeed, there is growing evidence that central metabolic pathways are linked to virulence in many bacterial pathogens.

Recently, 13

CO2-pulse-chase experiments have elucidated the biosynthetic origin of commercially and medicinally important food additives and drugs from plants. The knowledge about metabolism in plants under physiological conditions is crucial in the interpretation of positional isotope ratios also for the fu-ture assignment of plant product authenticity.

13

V 13 Compound-specific labelling traces metabolic carbon allocation into plant volatile organic compounds and CO2

C. Werner1, F. Wegener

1, K. Jardin

2

1Universität Bayreuth, Bayreuth, Deutschland

2Universität Berkley, Berkley, Vereinigte Staaten von Amerika

Plant metabolic processes exert a large influence on global climate and air quality through the emis-sion of the greenhouse gas CO2 and volatile organic compounds (VOCs). Despite the enormous im-portance, processes controlling plant carbon allocation into primary and secondary metabolism, such as respiratory CO2 emission and VOC synthesis, remains unclear.

The vegetation exerts a large isotopic imprint on the atmosphere through both, photosynthetic carbon isotope discrimination and fractionation during respiratory CO2 release (δ

13Cres). While the former is

well understood, many processes driving carbon isotope fractionation during respiration are unknown. There are striking differences in variations of δ

13Cres between plant functional groups, which have been

proposed to be related to carbon partitioning in the metabolic branching points of the respiratory path-ways and secondary metabolism, which are linked via a number of interfaces including the central me-tabolite pyruvate. Notably, it is a known substrate in a large array of secondary pathways leading to the biosynthesis of many volatile organic compounds (VOCs), such as volatile isoprenoids, oxygenat-ed VOCs, aromatics, fatty acid oxidation products, which can be emitted by plants.

Here we investigate if carbon isotope fractionation in light and dark respired CO2 is associated with VOC emissions in the atmosphere. Specifically, we hypothesize that a high carbon flux through the py-ruvate into various VOC synthesis pathways is associated with a pronounced

13C-enrichment of re-

spired CO2 above the putative substrate, as it involves the decarboxylation of the 13

C-enriched C-1 from pyruvate.

Based on simultaneous real-time measurements of stable carbon isotope composition of branch re-spired CO2 (CRDS) and VOC fluxes (PTR-MS) we traced carbon flow into these pathways by pyruvate positional labeling.

We demonstrated that in a Mediterranean shrub the 13

C-enriched C-1 from pyruvate is released in substantial amounts as CO2 in the light. Simultaneously, naturally

13C depleted C-2 and C-3 carbon

atoms of the acetyl-moiety are emitted as a variety of VOCs. Moreover, during light-dark transitions leaf emission bursts of the oxygenated metabolite acetaldehyde were observed as part of the PDH bypass pathway in the cytosol

2. This may be a new piece of evidence for the origin of

13C-enriched

δ13

CO2 which is released during Light-Enhanced Dark Respiration (LEDR).

Our study provides the first evidence that the isotopic signature of respired CO2 is closely linked to carbon partitioning between anabolic and catabolic pathways and plants strategies of carbon invest-ment into secondary compound synthesis.

References

Werner C. & Gessler A. (2011) Diel variations in the carbon isotope composition of respired CO2 and associated carbon sources: a review of dynamics and mechanisms. Biogeosciences 8, 2437-2459

Jardine K, Wegener F, Abrell L, vonHaren J, Werner C (2014) Phytogenic biosynthesis and emission of methyl acetate. PCE 37, 414-424.

14

V 14 What determines δ

13CO2 during light enhanced dark respiration (LEDR)?

M. M. Lehmann1, F. Wegener

2, M. Barthel

3, C. Werner

2, N. Buchmann

3, R. T. W. Siegwolf

1,

R. A. Werner3

1Paul Scherrer Institute (PSI), Laboratory of Atmospheric Chemistry, Villigen, Schweiz

2University of Bayreuth, Agro-Ecosystem Research, Bayreuth, Deutschland

3ETH Zurich, Institute of Agricultural Sciences, Zurich, Schweiz

Transferring light-acclimated leaves into complete darkness causes an immediate enhancement of CO2 respiration rates, which is known as “light enhanced dark respiration” (LEDR). During this meta-bolic transition between photosynthesis and respiration, leaf dark-respired CO2 (δ13CLEDR) can be heavily enriched in 13C (up to 16‰ compared to potential respiratory substrates). It was suggested that δ13CLEDR is determined by the C-4 position of malate, which should be 13C enriched compared to other molecule position due to an anapleurotic flux via the phosphoenolpyruvate carboxylase reac-tion. The C-4 position itself can be released by the mitochondrial malic enzyme reaction (mtME), which in turn might determine δ13CLEDR. However, experimental evidence for that mechanism is still lack-ing. Hence, we fed leaves via the xylem stream with position-specific labelled malate (13C-1, 13C-4) and pyruvate (13C-1, 13C-2) to determine the influence of different substrates on δ13CLEDR. Respir-atory fluxes of 13CO2 were measured during light-dark transition courses of about 20 min in the light and 20 min in the dark using laser spectroscopy in Arabidopsis thaliana species (wild type and mutant) and in species differing in δ13CLEDR (Halimium halimifolium, Oxalis triangularis). δ13CLEDR of Arabidopsis wild type and mutant (nadme1x2; fully lacking mtME) did not differ at natu-ral abundances. Also light dark-transition courses of mean 13CO2 fluxes of 13C-4 malate treated Ara-bidopsis plants showed no difference in their peak form, suggesting a minor relevance of mtME im-printing on δ13CLEDR. Furthermore, light-dark transition courses of mean 13CO2 fluxes of 13C-1 malate and 13C-1 pyruvate treated H. halimifolium and O. triangularis plants showed clear peaks shortly upon darkening, which were similar or higher compared to 13C-4 malate treated plants. This demonstrates that δ13CLEDR is not solely determined by mtME and by the C-4 position of malate and that also other enzymatic reactions and substrates must have a crucial role during LEDR.

15

V 15 αStable Carbon Isotope Fractionation in human Steroid Metabolism

U. Flenker1, P. Riemann

1, A. Macha

1, V. Gougoulidis

1, N. Haenelt

1, F. Hülsemann

1, M. K. Parr

2,

W. Schänzer1

1Deutsche Sporthochschule Köln (DSHS), Institut für Biochemie, Köln, Deutschland

2Freie Universität Berlin, Institut für Pharmazie, Berlin, Deutschland

Most metabolic pathways are characterized by multiple branch points. If at least one of the branches features an isotope effect, this eventually will effect isotope fractionation. Typically, depletion of the heavy isotopes occurs on the product side. Theoretically, the isotope ratios of both products will then be largely controlled by relative proportions of the metabolic fluxes. In steady-state, these effects occur in parallel, i. e. the difference between the isotope ratios of the products remains constant.

In human steroid metabolism, this phenomenon can be observed for the intra-individual variance pre-sent in the

13C/

12C ratios of the two abundant androgen metabolites androsterone (A) and

etiocholanolone (E). These originate from identical substrates and thus represent a branched pathway. In accordance with population based reference data, E is consistently depleted in

13C vs. A. This sug-

gests presence of a significant isotope effect during steroid 5β-reduction which yields E. By contrast, 5α-reduction yields A. Both reactions are crucial in that they represent initial and rate limiting steps in steroid metabolism.

The phenomenon can be observed best in individuals who excrete comparably large total amounts of A and E. Again, this is consistent with theory, because A and E then possibly reflect a large proportion of gross androgen metabolic flux. Moreover, lower concentrations of E and A are associated with low-er

13C/

12C ratios of both compounds. This will be consistent with mass balance if an isotope effect for

the reduction of the Δ4-bond is assumed, but suggests significant contributions of additional catabolic

pathways.

In contrast to physiological variations of metabolic fluxes, the administration of drugs will typically cause massive disturbances of the steady-state. Usually, the substrate input temporarily surpasses the maximum metabolic turnover. If the rate limiting metabolic step features an isotope effect, this will result in increasing accumulation of heavy isotopes in the substrate. Because the substrate is continu-ously metabolized, the isotope ratios of both, substrate and metabolites, will then increase systemati-cally.

Consistent with these considerations, the bolus administration of 19-norandrostenedione results in in-creasing

13C/

12C ratios of its 5β-metabolite 19-noretiocholanolone. Corresponding effects can be ob-

served after boldenone administration. An increase of the 13

C/12

C ratios of ca. 4 ‰ can be observed within 40 h. Boldenone itself as well as its 5β-metabolite can be affected.

These findings nicely reflect and illustrate the principles of isotope fractionation processes in metabolic networks. Practically,

13C/

12C analysis of the mentioned steroids is heavily employed to detect andro-

gen abuse in sports drug testing. Our findings can therefore significantly support the interpretation of corresponding data. More generally, reliable source assignment of drugs based on isotope analysis of urinary compounds may be significantly be impeded by these phenomena.

16

V 16 Abiotic methanogenesis from organosulfur compounds under ambient conditions and its potential implications for methane formation in eukaryotes

F. Keppler1, F. Althoff

1, K. Benzing

1,2, P. Comba

2, C. McRoberts

3, D. Boyd

4, K. Lenhart

5, S. Greiner

6

1Universität Heidelberg, Institut für Geowissenschaften, Heidelberg, Deutschland

2Universität Heidelberg, Anorganisch-Chemisches Institut, Heidelberg, Deutschland

3Agri-Food and Biosciences Institute, Belfast, Irland

4Queen´s University Belfast, School of Chemistry & Chemical Engineering, Belfast, Irland

5Universität Gießen, Pflanzenökologie, Gießen, Deutschland

6Universität Heidelberg, Centre for Organismal Studies, Heidelberg, Deutschland

The greenhouse gas methane (CH4) is the most abundant reduced organic trace gas in the atmos-phere and plays an important role in tropospheric and stratospheric chemistry. Various sources of CH4 are known to exist in nature and, recently, the number of suggested biological sources has been in-creased (1-4). However, the mechanism of CH4 formation in eukaryotes still needs to be elucidated and precursor compounds to be identified. In this presentation we introduce a chemical reaction that readily forms methane from organosulfur compounds under highly oxidative conditions at ambient at-mospheric pressure and temperature (5). Methyl groups of organosulfur compounds were shown to be efficiently converted into CH4 when using iron(II/III), hydrogen peroxide and ascorbic acid as reagents. In particular several S-methyl- substituted sulfides, sulfoxides and sulfonium salts such as L-methionine (MET), S-adenosylmethionine (SAM), dimethylsulfoniopropionate (DMSP) and dimethyl sulfoxide (DMSO) were studied. In a first step, methyl sulfides were oxidised to the corresponding sulfoxides. In the next step demethylation of the sulfoxide via homolytic bond cleavage led to methyl radical formation and finally to CH4 particularly at low local oxygen concentration. Because sulfoxidation of methyl sulfides is ubiquitous in the environment, this novel chemical route might mimic CH4 formation in living aerobic organisms such as plants, fungi, algae and mammals. Finally we stud-ied tobacco plants (Nicotiana tabacum) that were grown under sterile conditions and supplemented them with positionally labelled MET, where only the methyl group (-S-CH3) was enriched with

13C at-

oms. These experiments provided first evidence that MET, via its thio-methyl group, is a parent com-pound of CH4 in tobacco plants (5).

(1) Keppler, F., Hamilton, J. T. G., Braß, M., and Röckmann, T.: Methane emissions from terrestrial plants under aerobic conditions, Nature, 439, 187-191, 2006.

(2) Keppler, F., Boros, M., Frankenberg, C., Lelieveld, J., McLeod, A., Pirttilä, A. M., Röckmann, T., and Schnitzler, J.: Methane formation in aerobic environments, Environmental Chemistry, 6, 459-465, 2009.

(3) Lenhart, K., Bunge, M., Ratering, S., Neu, T. R., Schüttmann, I., Greule, M., Kammann, C., Schnell, S., Müller, C., Zorn, H., and Keppler, F.: Evidence for methane production by saprotrophic fungi, Nature Communications, 3, 1046, 2012.

(4) Ghyczy, M. et al. Hypoxia-Induced Generation of Methane in Mitochondria and Eukaryotic Cells - An Alternative Approach to Methanogenesis, Cell Physiol Biochem 21, 251-258, 2008.

(5) Althoff, F., Benzing, K., Comba, P., McRoberts, C., Boyd, D. R., Greiner, S., and Keppler, F.: Abiot-ic methanogenesis from organosulfur compounds under ambient conditions, Nature Communications, 5, doi: 10.1038/ncomms5205, 2014.

17

V 17 Online methods for the position specific analysis of

13C in some light organic compounds

N. Yoshida1,2,3

, T. Nimmanwudipong2, A. Gilbert

3, K. Yamada

1

1Tokyo Institute of Technology, Department of Environmental Chemistry and Engineering, Tokyo,

Japan 2Tokyo Institute of Technology, Department of Environmental Science and Technology, Tokyo, Japan

3Tokyo Institute of Technology, Earth-Life Science Institute,Tokyo, Japan

Position-specific isotopic analysis (PSIA) of organic compounds is expected to be used for plant me-tabolism studies, botanical source or the adulteration detection. For some organic compounds, such as ethanol, acetic acid and vanillin, PSIA has been available due to emergence of on-line pyrolysis-gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) [1] and quantitative isotopic

13C NMR spectroscopy [2]. Here we present recent advances in PSIA of light organic com-

pounds.

First, we picked up ethanol, which δ13

C value can be a useful indicator for authentication purpose. We developed the measurement method of the molecular and intramolecular δ

13C value of ethanol in

aqueous solution using an on-line pyrolysis- GC-C-IRMS [3]. The 13

C values of the pyrolytic fragments (CO, CH4) can be measured with high repeatable result (S.D.<0.4‰) using the system, allowing cor-recting factors to be applied in order to back-calculate the original δ

13CCH2OH and δ

13CCH3 values of

ethanol. The method allows the determination of the δ13

C value of ethanol at the intramolecular and molecular levels, within a single run and a short experimental time (30 min), and with an easy sample preparation.

Other example of the popular and important chemical compounds is vinegar which is mainly consisting of acetic acid. Lately, the adulterations of acetic acid with other dangerous compounds have been found spread wide over the world. In other words, the intramolecular d

13C distribution of acetic acid

can be very useful to avoid the poisonous agent, which can be mixed with the original materials. Acetic acid can be pyrolyzed and results in three main fragments (CO, CH4, CO2). CO2 fragment is corre-sponded to carboxyl part (COOH) while we expect the CH4 fragment should correspond to methyl part (CH3). Using five acetic acid standards to make the calibration curve and then we make the single in-jection with head space-solid phase micro-extraction (HS-SPME) into GC-Py-GC-C-IRMS system. Comparing with the offline pyrolysis method [4], the d

13C have the repeatable result about <0.3 ‰ and

<0.9‰ for COOH and CH3 part respectively with the easy sample preparation with short experimental time (30mins) [5]. This method will also be very useful for applications of acetic acid and many study which is related to.

[1] E.Caytan et al. (2007), Anal. Chem., 79, 8266

[2] T.N.Corso and J.T.Brenna (1997), PNAS, 94(4), 1049

[3] A.Gilbert et al. (2013), Anal.Chem., 85, 6566

[4] K.Yamada et al. (2014), Rapid Commun.Mass Spectrom., 28, 1821

[5]T.Nimmanwudipong et al. (2014), to be submitted to IEHS

18

V 18 N2O production pathways in a partial nitritation-anammox reactor: Isotopic evidence for N2O production associated with anaerobic NH4

+ oxidation?

E. Harris1, P. Wunderlin

2, A. Joss

2, L. Emmenegger

1, M. Kipf

2, H. Siegrist

2, B. Wolf

3, J. Mohn

1

1Empa, Dübendorf, Schweiz

2EAWAG, Dübendorf, Schweiz

3IMK-IFU, Garmisch-Partenkirchen, Deutschland

Nitrous oxide is a strong greenhouse gas and the most important stratospheric ozone-depleting sub-stance released in the 21

st century

1. Microbial N2O production during wastewater treatment is an im-

portant and growing source of N2O. This study presents the first online isotopic measurements of offgas N2O from a 400 L pilot scale, single-stage partial-nitritation anammox reactor. The N2O produc-tion pathways in the reactor are inferred based on the measured N2O isotopic composition - in particu-lar the N2O isotopic site preference (SP = δ

15N

α - δ

15N

β), which is characteristic for different N2O pro-

duction pathways2-5

.

N2O emissions were investigated both under normal (optimal) operating conditions and during a num-ber of experiments, designed to cover the range of conditions commonly encountered during operation (Figure 1). When N2O emissions peaked due to high dissolved O2 (‘high aeration’ in Figure 1), low SP showed that N2O was produced primarily via nitrifier denitrification by ammonia oxidizing bacteria (AOBs). N2O production by AOBs via NH2OH oxidation, in contrast, did not appear to be important un-der any conditions.

Figure 1. N2O site preference and N2O emissions per NH4+ consumed (N2O/NH4

+; %) over a range of

experiments conducted with a single-stage partial nitritation-anammox reactor. Expected ranges for N2O production via NH2OH oxidation (biotic and abiotic) or denitrification are shown in blue and green respectively

2-5; the red range indicates the measured SP values that cannot be explained by currently

known N2O production pathways.

Over the majority of the one-month measurement period, the measured SP was much higher than ex-pected, reaching 41‰ during normal operating conditions and achieving a maximum of 45‰ when ni-trite was added under anoxic conditions (Figure 1). An unknown N2O production pathway with SP >45‰ mediated by anammox bacteria was the explanation most consistent with the results, although the possibility of strong N2O reduction by heterotrophic denitrifiers could not be entirely discounted

6.

1.Ravishankara et al. (2009) Science, 326 (5949): 123-125 2. Wunderlin et al. (2013) Environmental Science and Technology, 47 (3): 1339-1348 3. Sutka et al. (2006) Applied and Environmental Microbiology, 72: 638-644 4. Toyoda et al. (2011) Global Biogeochemical Cycles, 25, doi:10.1029/2009GB003769 5. Heil et al. (2014) Geochimica et Cosmochimica Acta, 139: 72-82. 6. Ostrom et al. (2007) Journal of Geophysical Research - Biogeosciences, 112, doi: 10.1029/2006JG000287

Anhang 1

19

V 19 Elementkonzentrations- und Isotopenverhältnisbestimmungen an menschlichen Haarsträhnen mittels induktiv gekoppeltes Plasma-Massenspektrometrie (ICP-MS) und Isotopenverhältnis-Massenspektrometrie (IRMS)

N. Scheid1, M. Dücking

1, T. Holdermann

2, S. Schneiders

2, P. Weis

1

1Bundeskriminalamt, KT 13 - Materialuntersuchungen Anorganik, Wiesbaden, Deutschland

2Bundeskriminalamt, KT 12 - Zentrale Analytik II, Wiesbaden, Deutschland

Die Isotopenanalyse von Skelett- und Geweberesten für die Bestimmung der Herkunft, Lebensweise und Mobilität von vorzeitlichen Menschen und Tieren hat in den letzten Jahrzehnten in der Archäolo-gie, Anthropologie und Paläontologie stark an Bedeutung gewonnen [1]. Auch auf dem Gebiet der Fo-rensik wurden Isotopenverhältnisse leichter (C, N, H, O, S) und schwerer (Sr, Pb) Elemente zur Her-kunftsbestimmung unbekannter Toter verwendet (vgl. z. B. [2]). Um festzustellen, inwieweit aus element- und isotopenanalytischen Untersuchungen belastbare Er-kenntnisse über Herkunft, Wohnort und/oder mögliche Ortswechsel von Personen gewonnen werden können, werden Analysen an humanbiologischen Materialien aus der Gegenwart (Haare und Finger-nägel) durchgeführt. Die Proben stammen von 3 unterschiedlichen Personengruppen: zu Gruppe 1 zählen Personen, die im Großraum Mainz/Wiesbaden leben und nur urlaubsbedingte Ortswechsel vornehmen (Referenzpo-pulation). In Gruppe 2 werden deutsche Staatsbürger zusammengefasst, die berufsbedingt für einige Monate bis hin zu einigen Jahren einen Aufenthalt im Ausland wahrnehmen. Zur 3. Gruppe zählen Personen, die aus dem Ausland stammen und sich für einige Monate beruflich in Deutschland aufhal-ten. Von Personen aus diesen 3 Gruppen werden vor und während eines Auslandsaufenthalts Haare und Fingernagelproben genommen. Diese Probennahme erfolgt auf freiwilliger Basis und alle perso-nenbezogenen Daten werden anonymisiert. Die elementanalytischen Untersuchungen der Proben werden mittels ICP-MS (Agilent 7700x, Santa Clara CA, USA) durchgeführt. Bei Verwendung des Desolvationssystem APEX Q (Firma ESI, Elemental Scientific Inc., Omaha, NE, USA) ist eine Probeneinwaage von 0,5 mg für die Analyse aus-reichend. Die Isotopenverhältnis-Bestimmungen der Proben werden mittels EA-IRMS (Flash EA 1112, Thermo-Fisher Scientific, Bremen; IRMS Typ Delta V plus, Thermo Scientific, Bremen) durchgeführt. Im Vortrag/Poster werden die Elementkonzentrationsergebnisse der Haarproben mit den Ergebnissen aus den Isotopenverhältnisbestimmungen verglichen und diskutiert. Inwieweit diese Ergebnisse einen Hinweis auf einen getätigten Ortswechsel des Haarspenders liefern, soll ebenfalls erörtert werden. [1] Tütken,Thomas (2010) Die Isotopenanalyse fossiler Skelettrest - Bestimmung der Herkunft und Mobilität von Menschen und Tieren. Tagungen des Landesmuseums für Vorgeschichte Halle, Band 3, 33-51. [2] Rauch,E., Rummel,S., Lehn,C., & Büttner,A. (2006) Origin assignment of unidentified corpses by use of stable isotope ratios of light (bio-) and heavy (geo-) elements- a case report. Forensic Science International, 168, 215-218.

20

V 20 Global spatial distribution of natural stable carbon and nitrogen isotope ratios in modern hu-mans

F. Hülsemann1, T. Piper

2, C. Lehn

3, S. Schneiders

4, U. Flenker

1, W. Schänzer

1

1Deutsche Sporthochschule Köln, Institut für Biochemie, Köln, Deutschland

2Deutsche Sporthochschule Köln, Zentrum für präventive Dopingforschung, Köln, Deutschland

3LMU München, Institut für Rechtsmedizin, München, Deutschland

4BKA Wiesbaden, Wiesbaden, Deutschland

Natural stable carbon (δ13

C) and nitrogen isotope ratios (δ15

N) of modern human tissue and (excreted) metabolised products are related to the individual's dietary habits and geographical origin. It is known that geographical differences in the isotope ratio of human diets are detectable by stable isotope anal-ysis of e.g. fingernail and hair, as well as in urinary steroids. In forensic science the stable isotope analysis of human remains like bone, hair and fingernails is used for geographical allocation of the in-dividual. Human δ

13C values are primarily correlated to the proportion of C3-, and C4-plants in the diet.

Due to differences in the biosynthetic pathways C4-plants like maize, sugar cane, and sorghum show increased δ

13C values compared to C3-plants like wheat or potatoes. These differences can be de-

tected by δ13

C analysis of e.g. human hair or urinary steroids. In general, human δ13

C values decrease with increasing latitude of the individual's residence. Thus, lowest δ

13C values are found for Scandina-

vian samples, whereas highest δ13

C values are found for subjects originating from Brazil. In contrast to carbon, the global spatial distribution of human δ

15N values is apparently not exclusively related to die-

tary but also to environmental factors.

In doping analysis individual δ13

C values of endogenous reference compounds (ERC) are used for the interpretation of a potential exogenous origin of target metabolites. Thus, geographical differences in the δ

13C values of ERCs may have an influence of the interpretation of such stable isotope analyses.

The knowledge of the global spatial distribution of natural stable carbon isotope ratios of humans is one component in the interpretation of isotope ratio measurements of endogenous reference com-pounds in doping control as it is in forensic science. However, up to now no substantial global data sets on global human carbon (and nitrogen) isotope ratios are available, although for forensic investi-gations the amount of available data on human isotope ratios has increased within the last years. Hair is the preferred matrix in forensic stable isotope analysis due to the non-invasive sampling and com-paratively easy analysis compared to the laborious and complex stable isotope analysis of urinary steroids. Information about global distribution of δ

13C values of human hair can be used for the inter-

pretation of δ13

C values found for endogenous reference compounds in doping control as well as for educational purposes and general understanding of spatial patterns of natural stable carbon isotope ratios.

21

Vorträge

Session 4 – Geochemische Stoffkreisläufe und Schadstoffdynamik

V 21 Calibration of (

13C/

12C and

2H/

1H)-isotope ratios in methane

W. A. Brand1, N. Uitslag

1, P.Sperlich

1, H. Geilmann

1, M. Rothe

1, J. Richter

1

1MPI BGC Jena, Isolab, Jena, Deutschland

Methane is the second largest anthropogenic greenhouse gas present in the atmosphere. Methane concentrations in the atmosphere have more than doubled since the beginning of the industrial era. The more or less steady increase over time was interrupted from ~ 2000 to 2008, after which the in-creasing trend resumed. The cause of this change has been subject of a large debate among the sci-entists, but an agreement about the underlying mechanisms is still pending.

Several atmospheric models and scenarios have been proposed to explain this change. Quantitative results from such models can be verified with measurements of methane concentrations as well as its isotope ratios. Isotope measurements are used to partition the sources and sinks and verify model re-sults. The required high-precision measurements are made in several specialized laboratories around the globe, analyzing samples from a large number of stations.

Comparisons of measurement results between different laboratories for samples from the same loca-tion have revealed scale offsets mainly for the stable isotope measurements; mole fraction measure-ments have turned out to be more consistent. Neglecting such offsets can lead to substantial modeling errors. A cross-network calibration is needed to take care of these effects. However, there are no in-ternationally accepted reference materials for the stable isotopes of CH4 in air available, yet. In this work, a start has been made in this direction, which should lead finally to an established independent scale for the CH4 isotopes.

Eight methane cylinders have been calibrated against the international reference materials for δ13

C and δ

2H. We calibrated one methane gas directly against the international standards for δ

13C and δ

2H,

LSVEC and NBS 19 (Mar-j1), and VSMOW respectively. This was done by converting the methane and carbonates directly to CO2 in an elemental analyzer, and measuring the CO2 in an isotope ratio mass spectrometer (IRMS). Methane and water were converted at a temperature of 1450 °C to H2, which was measured in an IRMS. Seven other methane gases have been compared to the first me-thane gas by injecting them alternating into each system. An extended error analysis was done to ac-count for the complete error budget. For δ

13C a range of −39 ‰ to −70 ‰ is covered; for δ

2H a range

of − 320 ‰ to + 44 ‰ is covered. The new calibrated methane gases were mixed into methane free air for a comparison to the current scale. The comparison of this new scale to the current local scale shows an offset for carbon of +0.066 ± 0.0157 ‰; for hydrogen the offset is + 3.97 ± 1.056 ‰. Also, the local current scale is compared to the scale of the Institute for Marine and Atmospheric Research in Utrecht by measuring 10 air flasks from Lutjewad. The results show an offset of +3.82 ± 4.28 ‰ for δ

2H, and an offset of −0.22 ± 0.33 ‰ for δ

13C; The relatively large uncertainties are due to the low

pressure in the flasks (below 1 bar) that affects the flow measurements in the IRMS and thus the iso-topic measurements.

22

V 22 Kann die Sauerstoffisotopensignatur in N2O zur Bestimmung des pilzlichen Anteils an der De-nitrifikation genutzt werden?

L. Rohe1,2

, T.- H. Anderson2, G. Braker

3,4, H. Flessa

2, A. Giesemann

2, D. Lewicka-Szczebak

2,

N. Wrage-Mönnig1,5

, R. Well2

1Georg-August-Universität Göttingen, DNPW Graslandwissenschaft, Göttingen, Deutschland

2Thünen-Institut für Agrarklimaschutz, Braunschweig, Deutschland

3Max Plank Institut für terrestrische Mikrobiologie, Marburg, Deutschland

4Christian-Albrechts-Universität Kiel, Cluster of Excellence 'The Future Ocean', Kiel, Deutschland

5Universität Rostock, Professur Grünland und Futterbauwissenschaften, Rostock, Deutschland

Welchen Anteil Pilze an der N2O Bildung durch die Denitrifikation im Boden haben ist bisher weitge-hend unerforscht. Bisher galt die

15N Positionspräferenz im N2O als eine aussichtsreiche Messgröße,

um zwischen N2O aus der Denitrifikation von Pilzen und Bakterien unterscheiden zu können.[1]

Da Pil-ze und Bakterien während der Denitrifikation einen Sauerstoffaustausch (O Austausch) zwischen dem umgebenden Wasser und den Zwischenprodukten haben, wurde die

18O Signatur im N2O bisher zur

Unterscheidung der Organismengruppen ausgeschlossen. Eigene Versuchsergebnisse deuten jedoch auf Unterschiede zwischen den

18O Signaturen im N2O beider Organismengruppen hin.

Pilzreinkulturen zeigten für N2O aus der Denitrifikation d18

O Werte von 33 bis 55‰.[2, 3]

Der O Aus-tausch im Zuge der Denitrifikation wurde unter Verwendung von

18O angereichertem Wasser ermittelt

und lag zwischen 11% und vollen Austausch. Die Inkubation von zwei Bodentypen ergab, dass die Bodenorganismen N2O mit d

18O Werten von 4 bis 16‰ bei einem O Austausch von 93 bis 97% pro-

duzierten. Die gemessene 15

N Positionspräferenz deutete auf eine Dominanz der Bakterien bei der Denitrifikation in diesen Böden hin. Aus diesen Ergebnissen kann vermutet werden, dass die

18O Sig-

natur in von Pilzen gebildetem N2O weitaus höher ist als in N2O bakteriellen Ursprungs.

In weitergehenden Versuchen mit Reinkulturen von Pilzen und Bakterien wird mit variierender 18

O Signatur des Wassers der O Austausch und die Isotopenfraktionierung bei der N2O Produktion be-stimmt, um Aufschluss darüber zu erhalten, inwiefern sich die natürliche

18O Signatur des N2O von

Pilzen und Bakterien unterscheidet. Sollten die erwarteten Unterschiede bestätigt werden, könnte die 18

O Signatur des N2O neben der 15

N Positionspräferenz dazu dienen zwischen N2O pilzlichen bzw. bakteriellen Ursprungs zu unterscheiden.

Ein Fraktionierungsmodell[4, 5]

, das für die Denitrifikation von Bakterien entwickelt wurde, diente bei den oben genannten Pilzreinkulturversuchen zur Bestimmung der beteiligten Enzyme am O Aus-tausch. Dieses Modell soll nun eingesetzt werden, um zu testen, ob sich die Enzyme, die hauptsäch-lich den O Austausch katalysieren zwischen Pilzen und Bakterien unterscheiden und dadurch die Un-terschiede der

18O Signaturen im N2O entstehen. Erste Ergebnisse sollen vorgestellt werden.

References:

@END_ABSTRACT@

[1] C. Decock and J. Six. Soil Biol. Biochem., Vol. 65, 2013, pp. 114.

[2] L. Rohe, T.-H. Anderson, G. Braker, H. Flessa, A. Giesemann, D. Lewicka-Szczebak, N. Wrage-Mönnig and R. Well. Rapid Commun. Mass Spec., Vol. 28, 2014, pp. 1893.

[3] L. Rohe, T.-H. Anderson, G. Braker, H. Flessa, A. Giesemann, N. Wrage-Mönnig and R. Well. Rap-id Commun. Mass Spec., Vol. 28, 2014, pp. 377.

[4] D. M. Snider, J. J. Venkiteswaran, S. L. Schiff and J. Spoelstra. Geochim. Cosmochim. Ac., Vol. 112, 2013, pp. 102.

[5] K. L. Casciotti, J. K. Böhlke, M. R. McIlvin, S. J. Mroczkowski and J. E. Hannon. Anal. Chem., Vol. 79, American Chemical Society, 2007, pp. 2427.

23

V 23 δD and δ

13C measurements of chloromethane from terrestrial and extraterrestrial matter and its

implications for the search of organic matter on Mars

M. Greule1, F. Keppler

1, D. B. Harper

2, U. Ott

3, T. Sattler

1, H. Schöler

1, J. T. G. Hamilton

2

1Universität Heidelberg, Institut für Geowissenschaften, Heidelberg, Deutschland

2Queen’s University Belfast, School of Biological Sciences, Belfast, Irland

3Max-Planck-Institute for Chemistry, Mainz, Deutschland

Atmospheric chloromethane (CH3Cl) is an ozone depleting gas contributing ~16% of tropospheric chlorine. Most atmospheric CH3Cl is released from terrestrial vegetation with a significant fraction formed in dead and senescent leaf tissue, predominantly through an abiotic reaction between the me-thyl moiety of plant methoxyl groups (OCH3) and chloride. Controversy continues as to whether CH3Cl detected during pyrolysis of Martian soils by the Viking and Curiosity Mars landers is indicative of or-ganic matter indigenous to Mars (1-4). In this study we investigate the potential CH3Cl production from meteoritic matter. We present data obtained from the thermolysis (150 to 400°C) of samples of the Murchison meteorite (a well investigated carbonaceous chondrite of type CM2 that fell in Australia in 1969) both with and without chloride and perchlorate

- supplementation. Our results clearly demon-

strate formation of CH3Cl from organic matter of extraterrestrial origin and confirm unequivocally by stable isotope analysis the extraterrestrial origin of the methyl group. These observations are con-sistent with the well-documented release of chloromethane in the terrestrial environment from the methoxyl pool of organic matter in the presence of chloride (5-7) and provide a rationale for the chloromethane emissions recorded by Mars landers experiments. Our work suggests that methoxyl groups of the intact organic matter reaching the Martian surface can be converted to chloromethane on pyrolysis with perchlorate or chloride in Martian soil. Thus chloromethane release reported by pre-vious Mars landers is probably derived at least in part from organic matter from meteoritic debris alt-hough we do not discount an indigenous source. The stable carbon and hydrogen isotope signatures of chloromethane could potentially be utilized to determine the origin of chloromethane detected on Mars by distinguishing between terrestrial contamination, meteoritic infall and indigenous Martian sources. Indeed, for future planetary missions we suggest that chloromethane could be an important target compound for constraining the origin of any organics found.

(1) Biemann, K. et al. Search for organic and volatile inorganic compounds in 2 surface samples from Chryse-Planitia region of Mars. Science 194, 72-76, doi:10.1126/science.194.4260.72 (1976).

(2) Leshin, L. A. et al. Volatile, Isotope, and Organic Analysis of Martian Fines with the Mars Curiosity Rover. Science 341, 9, doi:10.1126/science.1238937 (2013).

(3) Navarro-Gonzalez, R., Vargas, E., de la Rosa, J., Raga, A. C. & McKay, C. P. Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars. J. Geophys. Res.-Planets 115, doi:10.1029/2010je003599 (2010).

(4) Ming, D. W. et al. Volatile and Organic Compositions of Sedimentary Rocks in Yellowknife Bay, Gale Crater, Mars. Science 343, 9, doi:10.1126/science.1245267 (2014).

(5) Hamilton, J. T. G., McRoberts, W. C., Keppler, F., Kalin, R. M. & Harper, D. B. Chloride methylation by plant pectin: An efficient environmentally significant process. Science 301, 206-209 (2003).

(6) Keppler, F., Kalin, R. M., Harper, D. B., McRoberts, W. C. & Hamilton, J. T. G. Carbon isotope anomaly in the major plant C-1 pool and its global biogeochemical implications. Biogeosciences 1, 123-131 (2004).

(7) Keppler, F., Harper, D. B., Rockmann, T., Moore, R. M. & Hamilton, J. T. G. New insight into the atmospheric chloromethane budget gained using stable carbon isotope ratios. Atmos. Chem. Phys. 5, 2403-2411 (2005).

24

V 24 Carbon, Nitrogen, and Hydrogen Isotope Analysis of N-Nitrosodimethylamine (NDMA) Formed During Chloramination of Ranitidine-Containing Waters

S. Spahr1, J. Bolotin

1, J. Schleucher

2, I. Ehlers

2, U. von Gunten

1, T. Hofstetter

1

1Eawag, Umweltchemie, Dübendorf, Schweiz

2Umea University, Umea, Schweden

Mitigation of N-nitrosodimethylamine (NDMA) and other hazardous water disinfection by-products (DBP) is currently hampered by a limited understanding of DBP formation mechanisms. We explored compound-specific stable isotope analysis (CSIA) to identify precursors and to delineate formation pathways of NDMA based on changes of its

13C/

12C,

15N/

14N, and

2H/

1H ratios. Solid-phase extraction

coupled to gas chromatography and isotope ratio mass spectrometry (SPE-GC/IRMS) enabled the ac-curate quantification of C, N, and H isotope ratios of NDMA and four additional N-nitrosamines in aqueous samples at concentrations of 0.6 μM (45 μg NDMA L

-1). In laboratory experiments,

chloramination of 3 μM of the pharmaceutical ranitidine resulted in NDMA formation with a yield of 97±4%. δ

2H and δ

13C values of NDMA remained stable during its formation. The δ

2H value of NDMA

corresponded well to the δ2H value of the N-(CH

3)2-group of ranitidine, which we measured using

quantitative deuterium nuclear magnetic resonance spectroscopy. This observation implies that the N-(CH

3)2-moiety of ranitidine is transferred to NDMA without being chemically altered. δ

15N of NDMA, in

contrast, increased owing to a normal 15

N-kinetic isotope effect associated with the cleavage of a bond to N in the rate-limiting step of NDMA formation. Our study illustrates how CSIA can contribute to the identification of NDMA precursors and formation pathways and thus support the design of effective mitigation measures.

25

V 25 Application of Compound-Specific Stable Isotope Analysis for Source Identification of Chlorin-ated Organic Pollutants

N. Ivdra1,2

, A. Fischer1,2

, S. Herrero-Martin2, H. Eisenmann

1, H.- H. Richnow

2

1Isodetect GmbH, Leipzig, Deutschland

2Helmholtz Centre for Environmental Research - UFZ, Department of Isotope Biogeochemistry,

Leipzig, Deutschland

Compound-specific isotope analysis (CSIA) is demonstrated to be an efficient tool to track sources and sinks of pollutants in the environment. In this study we have developed a concept for source iden-tification of chlorinated pesticides and their metabolites in soil. Organochlorine pesticides Hexachlorocyclohexane (HCH, 4 stereoisomers) and DDT were selected as model compounds for method development. In addition, potential metabolites of HCH (chlorinated benzenes) and most abundant metabolites of DDT (DDE and DDD) were included in the study.

Pure phase samples of HCHs and DDT were collected from different producers worldwide. Carbon stable isotope compositions (δ

13C) were measured by Elemental Analysis in tandem with Isotope Ratio

Mass Spectrometry (EA-IRMS). In addition, isotopic fingerprints of target insecticides were measured in solutions of agricultural and pharmaceutical formulations by Gas Chromatography coupled to IRMS via combustion unit (GC-C-IRMS). Obtained collection showed significant variability in stable carbon isotope ratios, exploring high potential for developed concept.

Preliminary analysis of chlorine stable isotope composition (δ37

Cl) of selected HCH samples showed a potential to distinguish between sources with similar δ

13C values. The analytical method for the deter-

mination of δ37

Cl by Dual-Inlet Isotope Ratio Mass Spectrometry (DI-IRMS)1,2

was optimized to im-prove its accuracy, using pure phase γ-HCH sample. The accuracy of the optimized method was test-ed by analysing CH3Cl sample with known δ

37Cl value reported vs. the SMOC scale (Standard Mean

Ocean Chloride) before and after the whole procedure. The difference between product and initial CH3Cl was 0.11 ± 0.04 ‰.

We tested well-known and novel techniques for extraction of semi-volatile compounds from soil sam-ples

3. All techniques were slightly modified from original procedures to be compatible with CSIA. For

method development we used a soil matrix, spiked with a mixture of target compounds with known iso-topic composition. Pre-concentration of the extract and different purification methods were also tested and optimized for compatibility with CSIA.

Most of the applied methods fulfilled the required accuracy for carbon isotope analysis of HCHs and chlorinated benzenes (isotopic composition was not significantly changed during extraction or purifica-tion procedures) and provided high extraction efficiencies for these compounds. Lower extraction effi-ciencies with related isotope effects were observed for DDT and its metabolites, when the water con-tent in the soil was increased. Accuracy and efficiency of the best combination of extraction and pre-concentration methods were validated on well-characterized soil samples, spiked with a mixture of tar-get compounds.

Results obtained in this study provide a concept for source identification of chlorinated pesticides in the environment. Moreover, the evaluation of different sample preparation techniques for carbon and chlorine isotope analysis will help to extend the possibilities of CSIA to a wider range of environmental applications.

References: 1. Jendrzejewski N., Eggenkamp H.G.M., Coleman M.L. Appl. Geochem., 2001, 16(9-10), 1021-1031. 2. Holmstrand H., Andersson P., Gustafsson O. Anal. Chem., 2004, 76(8), 2336-2342. 3. Ivdra N., Herrero-Martin S., Fischer A. J. Chromatogr. A, 2014, 1355, 36-45 Acknowledgements: 1. Tetyana Gilevska, Dr. Safdar Bashir, Dr. Matthias Gehre, Falk Bratfisch, Ursula Günther (Depart-ment of Isotope Biogeochemistry, UFZ), Dr. Magali Bonifacie (Institut de Physique du Globe de Paris) 2. Financial support by the European Union under FP7- People-ITN-2010 (Grant Agreement No. 264329)

26

V 26 Forensische Nutzung der IRMS: Profiling von „Crystal Meth“

S. Schneiders1, T. Holdermann

1, R. Dahlenburg

1

1Bundeskriminalamt, Kriminaltechnisches Institut, Wiesbaden, Deutschland

Mittels Isotopenverhältnismassenspektrometrie (IRMS) können zusätzliche Materialinformationen un-terschiedlichster forensisch relevanter Materialarten (Drogen, Klebebänder, Massenprodukte allge-mein, etc.) gewonnen werden, die häufig zur Erhöhung des Beweiswertes von Kriminaltechnik-Gutachten führen. Da jedes Material durch seinen Entstehungsprozess spezifische Änderungen der Isotopenverhältnisse erfährt, kann die IRMS sehr vielseitig eingesetzt werden. Beispielsweise kann die IRMS im Bereich der Sicherstellung von Betäubungsmitteln (BtM) einen wert-vollen Beitrag zum Materialvergleich leisten und auch bereits im Ermittlungsprozess als Mittel der „Forensic Intelligence“ eingesetzt werden. In Deutschland werden jedes Jahr einige illegale Laborato-rien zur Herstellung synthetischer Drogen, wie z.B. Amphetamin und Methamphetamin (Crystal Meth), aufgedeckt und darin befindliche Chemikalien sichergestellt. Für die Ermittlerseite ist es oft von Inte-resse zu wissen, ob an unterschiedlichen Orten sichergestellte Chemikalien und Endprodukte mit Ausgangschemikalien oder mit bestimmten Herstellungslabors in Verbindung gebracht werden kön-nen. Eine Übereinstimmung der Isotopenverhältnisse einer Tatprobe mit denen des Vergleichsmaterials ist z.B. ein Indiz für einen gemeinsamen Ursprung im Sinne eines Herstellungsprozesses. Je mehr Isoto-pe (z.B. Kohlenstoff, Stickstoff und Wasserstoff) dabei überprüft wurden, desto besser kann eine Zu-ordnung durchgeführt werden. Diese Präsentation stellt, anhand des Beispiels „Crystal Meth“, die IRMS als eine leistungsfähige Me-thode für Materialvergleiche in der Kriminaltechnik dar.

27

Vorträge

Session 5 – Klimaänderungen und -rekonstruktionen

V 27 Which climate factor does best explain carbon isotope variations in tree-rings: Temperature, precipitation or sunshine duration?

M. Saurer1, R. Siegwolf

1

1Paul Scherrer Institut, Villigen, Schweiz

Stable carbon isotope ratios in tree-rings have been successfully used for climate reconstruction for more than three decades now. Various climate parameters have been the target variable for recon-struction, ranging from temperature to precipitation or drought, and to sunshine duration, radiation or cloud cover. Yet, there is no clear pattern emerging where and why a certain climate variable is most important and often several factors seem to be co-dominant. Different species might also have differ-ent climate sensitivity. Based on the accepted isotope-fractionation model, all climate factors affecting stomatal conductance or photosynthesis are potentially important. Sunshine duration in high latitudes (photosynthesis not limited by water) has recently been suggested to dominate, while drought/precipitation is known to be reflected in carbon isotope variations in arid regions like the Southwestern United States. However, this obvious pattern is not always working. Generally, a nega-tive relationship between precipitation and δ

13C is prevailing throughout Europe, much more stable

than for ring-width, which shows clearly varying controls from South to North. A very strong regional drought-signal has been found for an Alpine larch site (Larix decidua), which seems counter-intuitive (Kress et al., 2014). Vegetation-model investigations could help to establish clearer patterns of differ-ent climate sensitivity of the carbon isotope ratios for different regions.

Reference Kress A, Hangartner S, Bugmann H, Büntgen U, Frank DC, Leuenberger M, Siegwolf R, Saurer M. (2014). Swiss tree-rings reveal warm and wet summers during medieval times. Geophysical Research Letters, 10.1002/2013GL059081

28

V 28 Die Mischung macht’s!? Facilitation zwischen adulten Buchen und Fichten im Trockenstress

T. Grams1, A. Feldermann

1, R. Matyssek

1

1Technische Universität München, Ecophysiology of Plants, Freising, Deutschland

Die Resilienz- und Resistenz gegenüber Trockenstress von adulten Buchen und Fichten wurden ent-lang eines Niederschlagsgradienten analysiert. Besonderes Augenmerk lag dabei auf dem Vergleich zwischen in Monokultur gewachsenen Buchen und Fichten mit Mischungen dieser beiden Arten am gleichen Standort. Der Stress-Gradienten-Hypothese folgend werden positive Interaktionen, d.h. Facilitationsinteraktionen, besonders unter limitierenden Wachstumsbedingungen erwartet. Die hier präsentierten Ergebnisse sind Teil eines größeren Projekts zu Facilitations- und Konkurrenz-Interaktionen von adulten Buchen und Fichten unter Trockenstress (kroof.wzw.tum.de).

Analysiert wurden Stammbohrkerne von Buchen und Fichten an 5 Standorte mit unterschiedlichen Niederschlagssummen während der Vegetationsperiode (zwischen 300 und 830 mm). Der Fokus lag auf dem Trockenjahr 2003 mit der vergleichenden Analyse der Resilienz und Resistenz von Buchen oder Fichten aus der Monokultur mit der gleichen Art aus der Mischkultur. Vor allem für die Buche ent-sprach das Wachstumsverhalten den Erwartung der Stress-Gradienten-Hypothese: Im Trockenjahr 2003 war der Jahrringzuwachs in der Mischung weniger stark reduziert als in den Monokulturen, d.h. die Resistenz gegenüber dem Trockenstress im Jahr 2003 war in der Mischung erhöht. Gleichfalls zeigten die in der Mischung gewachsenen Buchen eine verbesserte Resilienz als Buchen, die in der Monokultur gewachsen sind. Für Buchen waren diese Effekte vor allem auf den trockenen Standorten ausgeprägt, während Fichten die Verbesserung der Resilienz und Resistenz gegenüber dem Tro-ckenstress vor allem auf den feuchten Standorten zeigten. Diese Daten bestätigen den „Over-Yielding“-Effekt von Mischungen zwischen Buchen und Fichten, der vor allem auf armen Standorten ausgeprägt ist (Pretzsch et al. 2013).

Die gewonnenen Kohlenstoff-Isotopenverhältnisse aus den Jahrringen der Buchen und Fichten erga-ben allerdings ein anderes Bild: Beide Arten zeigten den für ein Trockenjahr typischen Anstieg des δ

13C im Jahrring auf allen Standorten. Allerdings waren für beiden Arten sowohl die Resilienz als auch

die Resistenz der Diskriminierung gegenüber 13

CO2 (Δ13

C) in der Mischung reduziert - vor allem für die Buchen auf den trockenen Standorten. Das heißt in der Mischung zeigte sich im Δ

13C eine erhöhte

Empfindlichkeit gegenüber dem Trockenstress und eine schwächere Erholung im Vergleich zur Mono-kultur. Gründe und Hypothesen für diesen gegenläufigen Trend zwischen Zuwachs und Kohlenstoff-isotopendaten werden diskutiert.

Pretzsch H, Schütze G, Uhl E (2013) Resistance of European tree species to drought stress in mixed versus pure forests: evidence of stress release by inter-specific facilitation. Plant Biology 15: 483-495.

29

V 29 Revisiting Mt. Kilimanjaro - reinterpreting δ

2H results of n-alkane biomarkers

M. Zech1,2

, R. Zech3, R. Kazimierz

4, A. Hemp

5, G. Gleixner

6, W. Zech

1

1Universität Bayreuth, Lehrstuhl für Geomorphologie, Bayreuth, Deutschland

2Martin-Luther-Universität Halle-Wittenberg, Bodenbiogeochemie, Halle, Deutschland

3Universität Bern, Geographisches Institut, Bern, Schweiz

4AGH University of Science and Technology, Faculty of Physics and Applied Computer Science,

Kraków, Polen 5Universität Bayreuth, Pflanzensystematik, Bayreuth, Deutschland

6Max-Planck Institut für Biogeochemie, Jena, Deutschland

During the last decade compound-specific deuterium (2H) analysis of plant leaf wax-derived n-alkanes

has become a promising and popular tool in paleoclimate research. This is based on the widely ac-cepted assumption that n-alkanes in soils and sediments generally reflect δ

2H of precipitation (δ

2Hprec).

Recently, several authors suggested that d2H of n-alkanes (δ

2Hn-alkanes) can also be used as proxy in

paleoaltimetry studies.

Here we present results from a δ2H transect study (~1500 to 4000 m a.s.l.) carried out on precipitation

and soil samples taken from the humid southern slopes of Mt. Kilimanjaro.

Figure 1

Contrary to earlier suggestions, a distinct altitude effect in δ2Hprec is present above ~2000 m a.s.l., i.e.

δ2Hprec values become more negative with increasing altitude (Fig. 1). The compound-specific δ

2H val-

ues of nC27 and nC29 do not confirm this altitudinal trend, but rather become more positive both in the O-layers (organic layers) and the Ah-horizons (mineral topsoils). Although our δ

2Hn-alkane results are in

agreement with previously published results from the southern slopes of Mt. Kilimanjaro (Peterse et al., 2009), a major reinterpretation is required given that the δ

2Hn-alkane results do not reflect the δ

2Hprec

results. The theoretical framework for this reinterpretation is based on the evaporative isotopic enrich-ment of leaf water associated with transpiration process. Modelling results show that relative humidity, decreasing considerably along the southern slopes of Mt. Kilimanjaro (from 78% in ~2000 m a.s.l. to 51% in 4000 m a.s.l.), strongly controls δ

2Hleaf water. The modelled

2H leaf water enrichment along the

altitudinal transect matches well the measured 2H leaf water enrichment as assessed by using the

δ2Hprec and δ

2Hn-alkane results and biosynthetic fractionation during n-alkane biosynthesis in leaves

(Zech et al., 2014) (Fig. 1).

Given that our results clearly demonstrate that n-alkanes in soils do not simply reflect δ2Hprec but rather

δ2Hleaf water, we conclude that care has to be taken not to over-interpret δ

2Hn-alkane records from soils

and sediments when reconstructing δ2H of paleoprecipitation. Both in paleoaltimetry and in

paleoclimate studies changes in relative humidity and consequently in δ2Hn-alkane values can complete-

ly mask altitudinally or climatically-controlled changes in δ2Hprec.

References

Peterse F., van der Meer M., Schouten S., Jia G., Ossebaar J., Blokker J., and Sinninghe Damsté J.: Assessment of soil n-alkane δD and branched tetraether membrane lipid distributions as tools for paleoaltitude reconstruction, Biogeosciences, 6, 2799-2807, 2009.

Zech, M., Zech, R., Rozanski, K., Hemp, A., Gleixner, G. and Zech, W.: Revisiting Mt. Kilimanjaro: Do n-alkane biomarkers in soils reflect the δ

2H isotopic composition of precipitation?, Biogeosciences

Discussions, 11, 7823-7852, doi:10.5194/bgd-11-7823-2014.

Figure 1: Altitudinal change of δ2Hprecipitation, δ

2Halkanes, and

2H enrichment of leaf water (depending pri-

marily on relative humidity). 1)

From Peterse et al., 2009

30

Anhang 1

31

V 30 Reconstructing lake evaporation history and the isotopic composition of precipitation by a coupled δ

18O-δ

2H biomarker approach

J. Hepp1,2

, M. Tuthorn1,2

, R. Zech3, I. Mügler

4, F. Schlütz

5, W. Zech

1, M. Zech

1,2

1Universität Bayreuth, Lehrstuhl für Geomorphologie, Bayreuth, Deutschland

2Martin-Luther-Universität Halle-Wittenberg, Bodenbiogeochemie, Halle, Deutschland

3Universität Bern, Geographisches Institut, Bern, Schweiz

4Max-Planck Institut für Biogeochemie, Jena, Deutschland

5Universität Göttingen, Abteilung Palynology, Göttingen, Deutschland

Over the past decades, δ18

O and δ2H analyses of lacustrine sediments became an invaluable tool in

paleohydrology and paleolimnology for reconstructing the isotopic composition of past lake water and precipitation. However, based on δ

18O or δ

2H records alone, it can be challenging to distinguish be-

tween changes of the precipitation signal and changes caused by evaporation. Here we propose a coupled δ

18O-δ

2H biomarker approach that provides the possibility to disentangle between these two

factors (Fig. 1).

Figure 1

The isotopic composition of long chain n-alkanes (n-C25, n-C27, n-C29, n-C31) were analysed in order to establish a 16 ka Late Glacial and Holocene δ

2H record for the sediment archive of Lake Panch

Pokhari in High Himalaya, Nepal. The δ2Hn-alkane record generally corroborates a previously established

δ18

Osugar record reporting on high values characterising the deglaciation and the Older and the Young-er Dryas, and low values characterising the Bølling and the Allerød periods (Zech et al., 2014). Since the investigated n-alkane and sugar biomarkers are considered to be primarily of aquatic origin, they were used to reconstruct the isotopic composition of lake water (Fig. 1). The reconstructed deuterium excess of lake water ranges from +57‰ to -85‰ and is shown to serve as proxy for the evaporation history of Lake Panch Pokhari. Lake desiccation during the Deglaciation, the Older Dryas and the Younger Dryas is affirmed by a multi-proxy approach using the Hydrogen Index (HI) and the carbon to nitrogen ratio (C/N) as additional proxies for lake sediment organic matter mineralization (Hepp et al., 2014) (Figure 2).

Figure 2

Furthermore, the coupled δ18

O and δ2H approach allows disentangling the lake water isotopic enrich-

ment from variations of the isotopic composition of precipitation. The reconstructed 16 ka δ18

Oprecipitation record of Lake Panch Pokhari is well in agreement with the δ

18O records of Chinese speleothems and

presumably reflects the Indian Summer Monsoon variability.

References

Hepp, J., Tuthorn, M., Zech, R., Mügler, I., Schlütz, F., Zech, W., Zech, M., resubmitted. Reconstruct-ing lake evaporation history and the isotopic composition of precipitation by a coupled δ

18O-δ

2H bi-

omarker approach. resubmitted to Hydrology.

Zech, M., Tuthorn, M., Zech, R., Schluetz, F., Zech, W., Glaser, B., 2014. A 16-ka δ18

O record of la-custrine sugar biomarkers from the High Himalaya reflects Indian Summer Monsoon variability. Jour-nal of Paleolimnology 51, 241-251.

Figure 1: δ18

O-δ2H diagram illustrating the isotopic deviation of lake water (defined as deuterium-(d)

excess) from the Global Meteoric Water Line (GMWL). δ18

O values of hemicellulose-derived sugars (mean of arabinose, fucose and xylose; from Zech et al., 2014b) and δ

2H values of n-alkanes (mean of

n-C25, n-C27, n-C29, and n-C31) are used for reconstruction of the isotopic composition of Panch Pokhari lake water. δ

2H and δ

18O values of precipitation are calculated as intersections of the individ-

ual local evaporation lines (LEL) with the GMWL using a slope value of 4.2.

Figure 2: Comparison of (a) carbon to nitrogen (C/N) ratio, (b) Hydrogen Index (HI), and (c) deuterium-excess of lake water as proxies for evaporation history of Lake Panch Pokhari.

32

Anhang 1

Anhang 2

33

V 31 Isotopenpreisvortrag

D. Sachse1

1Universität Potsdam, Potsdam-Golm, Deutschland

34

Vorträge

Session 6 – Ökosysteme

V 32 Geographical patterns in the isotopic ecology of wool, past and present

I. von Holstein1

1Christian Albrechts Universität zu Kiel, Institut für Ur- und Frühgeschichte, Kiel, Deutschland

In medieval Europe, sheep wool was one of the most important industrial commodities involved in long-distance exchange. It was produced all over the continent in various grades, some of which were valued highly and traded widely. These trade flows were clearly already considerable by the 12

th cen-

tury, when substantial documentation begins. Archaeologists are interested in being able to trace the earlier beginnings of these economic processes, by identifying non-local textiles among the wool finds from waterlogged archaeological deposits.

A multi-isotopic sheep wool isoscape (δ13

C, δ15

N, unexchangeable δ2H and δ

18O) for northern Europe

is being developed, by analogy to food authenticity studies. This is based on data from modern wool (sampling sites n= 14, from Iceland to Finland), against which archaeological wool data (sampling sites n=5, sample n=102) is interpreted. Modern wool collection focused on fibre produced with rela-tively traditional grazing practices (no concentrate feeds, no artificial fertilizer on pasture), and mostly from heritage breeds. This presentation will demonstrate the construction of the isoscape, and discuss the ways in which modern sheep farming, and hence the modern sheep wool isoscape, differs sys-tematically from that of the medieval past. Potential methods of resolving these differences, including the use of data from archaeological sheep bone and modern vegetation, will be discussed.

35

V 33 It's Complex: Using 13C/15N plant and soil isoscapes to capture environmental gradients, land-management effects and land-use patterns across a NE German agricultural landscape

K. Nitzsche1, K. Premke

2, A. Geßler

1,3, Z. Kayler

1

1Leibniz Center for Agricultural Landscape Research (ZALF), Institute for Landscape Biogeochemistry,

Müncheberg, Deutschland 2Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Deutschland

3Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Schweiz

Agricultural landscapes are complex mosaics of landscape structures, vegetation, and land-use and management. Agricultural practices have the potential to mitigate or exacerbate climate change ef-fects, highlighting the need to understand their impact on ecosystem biogeochemical cycles. There are limited tools available to gain a landscape perspective of biogeochemical cycling and usually studies are carried out at the field or plot scale. To gain a wider perspective we produced isoscapes (isotopic landscapes) based on plant, soil and sediment organic matter in order to characterize the carbon, wa-ter and nitrogen relations of the landscape. We use the isotopic footprint to understand the effects of environmental gradients, land-management, and land-use at a scale that directly addresses the com-plexity of agricultural landscapes. Our research area is part of the Quillow catchment in the moraine landscape of NE Germany, which is heavily utilized for agriculture and consists of numerous land-scape features with different C/N dynamics. Typical landscape elements are small water bodies called “Sölle” (kettle holes), which are generally less than 1 ha in size, and which are interspersed across the landscape and predicted to undergo severe alterations in hydrology and biogeochemistry as the global climate changes. We collected plant and top-soil (2-15 cm) samples from a 38.2 km

2 rectangular area

of the catchment, sampling a 250 m grid in the main 2013 growing season. Moreover, we sampled sediment cores and plants from 50 kettle holes that represent the geomorphological and hydrological variability within the study area. We constructed isoscapes (δ

13C, Δδ

15N, iWUE, P) using geostatistical

interpolation and related them to multiple ecological processes both biotic and abiotic. On the basis of the intrinsic water use efficiency (iWUE) from crops, we are able to capture a small scale precipitation gradient. Generally, land-use types vary in their C/N dynamics and plants and soils are strongly linked and reflect land-management effects (e.g. fertilization, cultivation of maize) as well as the distance to urban areas. We can also show that the surrounding land-use type plays an important role on the bio-geochemical processes in kettle holes. We conclude that isoscapes represent promising tools when dealing with complex landscapes at regional scales and that there are given many possible applica-tions in terms of future biogeochemical and climate research.

36

V 34 Light limitation stimulates partial mycoheterothrophy in rhizoctonia-associated orchids

J. Schiebold1, M. I. Bidartondo

2, C. Kemnade

1, G. Gebauer

1

1Universität Bayreuth, BayCEER - Labor für Isotopen-Biogeochemie, Bayreuth, Deutschland

2Imperial College and Royal Botanic Gardens, Kew, Großbritannien

Partial mycoheterotrophy (PMH) is the ability of a plant to obtain carbon (C) and other nutrients from mycorrhizal fungi simultaneously to autotrophy [1]. PMH is a continuous nutritional mode in members of the Orchidaceae plant family associated with ectomycorrhizal fungi (ECM). For this group of orchids a clear interaction between light availability and the degree of PMH was shown. An increase in fungal C gain with decreasing local light availability is mirrored in natural

13C isotope signatures [2].

In this study we tested whether orchids with a mycorrhizal association with polyphyletic rhizoctonias show a similar light dependency of partial mycoheterotrophy under natural light climate gradients ana-lyzing d

13C, d

15N and d

2H isotope abundances. The two orchid species Ophrys insectifera L. and

Neottia ovata (L.) Bluff & Fingerh. growing in habitats ranging from mixed deciduous and coniferous forests strongly limited in light availability to open grasslands with rather high irradiation were sampled at two locations in the Nördliche Frankenalb (NE Bavaria). Leaf material of 12 orchid individuals per species and site and accompanying autotrophic non-orchid plants as references for site conditions [3] were resampled three times in the period of growth in 2012. Local light climate was continuously measured next to the sampled orchid individuals over the growing season. Stable isotope natural abundance analyses were conducted to test whether carbon (

13C) and nitrogen (

15N) are gained

through autotrophic means or via mycorrhizal fungi. In 2013 five orchid individuals per species and site and autotrophic references were sampled additionally to further analyze hydrogen (

2H) natural stable

isotope abundances.

O. insectifera and N. ovata individuals were significantly enriched in 13

C towards their autotrophic ref-erences at the forest site but not at the open grassland location. Contrasting the two species showed a significant enrichment in

15N at both sites except for N. ovata at the forest site where the orchid cannot

be distinguished from its reference species. Enrichment in 15

N in O. insectifera was significantly higher at the forest location. No temporal dynamics in

13C and

15N isotope abundances over the growing sea-

son were detected. N concentration was significantly higher towards autotrophic reference species at the forest site for both O. insectifera and N. ovata. Both species were significantly enriched in

2H to-

wards autotrophic references at the two sites. Our results demonstrate that local light availability also drives PMH in orchids associated with rhizoctonias as orchids at the light-limited forest site show a significant but proportionally smaller enrichment in

13C towards orchids mycorrhizal with ECM. Never-

theless, significant enrichment in 2H elucidates both rhizoctonia-associated orchids to be partially

mycoheterotrophic regardless of microscale light availability.

[1] V.S.F.T. Merckx, Mycoheterotrophy: An Introduction. In: V.S.F.T. Merckx (ed.) Mycoheterotrophy: The Biology of Plants Living on Fungi. (Springer, New York, 2013), pp 297-342.

[2] K. Preiss, I.K.U. Adam, G. Gebauer, Irradiance governs exploitation of fungi: fine-tuning of carbon gain by two partially myco-heterotrophic orchids, Proc. R. Soc. B 277, 1333-1336 (2010).

[3] G. Gebauer and M. Meyer, 15

N and 13

C natural abundances of autotrophic and myco-heterotrophic orchids provides insight into nitrogen and carbon gain from fungal association, New. Phytol. 160, 209-223 (2003).

37

V 35 Intramolecular isotope distributions detect CO2-driven increases in photosynthesis over centuries

I. Ehlers1, A. Augusti

1, T. Betson

1, M. Nilsson

2, J. Schleucher

1

1Umeå University, Umeå, Schweden

2Swedish University of Agricultural Sciences , Umeå, Schweden

The century time scale is most important for climate models, for prediction of crop productivity, and for adaptation to climate change. That plants respond on century time scales is demonstrated by ob-served changes in stomatal index, but beyond this, very little is known. We argue that this is because of a glaring gap of methods that can bridge between ecophysiological experiments and paleo science. We present new stable isotope methods that fill this gap, by providing information on metabolic fluxes on time scales of centuries.

Isotope measurements usually determine isotope ratios (e.g. δ13

C, δD) of whole molecules. However, it is well established that stable isotope abundance varies among intramolecular groups of metabo-lites, in other words each isotopomer has a distinct abundance. We have previously shown that this isotopomer variation reports on regulation of carbon metabolism.

Here, we apply deuterium (D) isotopomers to study the metabolic response of C3 plants to increasing atmospheric [CO2]. Greenhouse experiments show that D isotopomers of photosynthetic glucose de-pend on [CO2] during growth. This dependence constitutes an isotopomer signal of the metabolic flux ratio oxygenation : carboxylation at Rubisco, which is a central determinant of net primary production. The isotopomer ratio has significant advantages: First, the signal is based on an intramolecular iso-tope ratio, and is therefore independent of the isotope ratio of source water. Second, because it is based on metabolic fluxes at Rubisco, it integrates all parameters that affect the flux ratio oxygenation : carboxylation.

We traced this isotopomer signal in historic material of two crop species and two species from the nat-ural vegetation over the past 100 years and compared results with the greenhouse experiments. This allows estimating how much photorespiration has been reduced by the anthropogenic CO2 increase during the 20

th century, and shows that plants have not acclimated to increasing [CO2] during more

than 100 growing seasons.

This first demonstration of isotopomer signals of long-term metabolic changes shows that isotopomers carry physiological signals, which can be retrieved from archives of plant material. Because D is frac-tionated both in the climate system and in biochemical reactions, D isotopomers of long-term archives of plant material may allow derivation of parallel physiological and climate signals, which may reveal plant-climate interactions. The principles governing isotopomer abundances are general for all me-tabolites and isotopes (D,

13C), therefore isotopomers multiply the information content of paleo ar-

chives. In particular, they allow extraction of metabolic information on long time scales, thereby con-necting plant physiology with paleo research.

38

V 36 Investigations of (soil) respiration in a long-term Free Air CO2 Enrichment (FACE) experiment

K. Lenhart1, C. Müller

2, C. Kammann

2

1Insitut für Pflanzenökologie, Professur für Geoökologie und Modellbildung, Gießen, Deutschland

2Institut für Pflanzenökologie, Experimentelle Pflanzenökologie, Gießen, Deutschland

The increased C supply with increasing atmospheric CO2 conditions enhances photosynthesis but al-so increases respiratory C losses from ecosystems with a yet unknown net effect for the net soil C stock. FACE experiments are an established tool in ecological research studies to investigate the be-havior of ecosystems to increased atmospheric CO2 concentrations under natural conditions in the field with only minor artificial effects.

Here we present 13

C signature values of several ecosystem compartments and from soil and ecosys-tem respiration of a permanent grassland ecosystem. After six years, the δ

13C value of the enrich-

ment-CO2 was switched from -25 to -48‰, to trace ecosystem C-fluxes without concomitant priming effects of the initial CO2 step increase. To obtain a general picture on the C fluxes soil and plant sam-ples were taken to measure carbon (C) pools and stable carbon isotope values. Gas samples were collected from soil air and ecosystem respiration (Reco) to measure CO2 concentration and δ

13C value

of CO2 (δ13

CO2).

We observed an annual trend of the δ13

CO2 value on Reco and soil air CO2. The δ13

CO2 of Reco and soil air CO2 showed lowest values during the growth period, indicating a higher contribution of plant-derived CO2 at that time. Based on the δ

13C values of plants and soil C we calculated the contribution

of plants and soil on respiration via two-component mixing model. Under elevated CO2 +20%, the es-timated contribution of root-derived soil respiration was 55% in the top 15 cm of the soil. The mean contribution of root, leaf and soil respiration on Reco was 29 ±18%, 32 ±23% and 38 ±20%, respective-ly. A significant decrease in soil air δ

13CO2 with soil depth indicated a relatively higher contribution of

root-derived CO2 in the deeper soil layers. The δ13

CO2 gradient showed a clear annual dynamics with a significant impact of soil temperature. The steepest δ

13CO2 gradients occurred during winter but be-

came less distinctive during summer.

During the observation period the CO2 enrichment enhanced Reco by 13% above ambient but did not result in increased soil C sequestration after 9 years of elevated CO2. No CO2-induced differences in the temporal dynamics of Reco, soil air [CO2] and the δ

13C values were observed. The seasonal varia-

bility recorded in the long-term monitoring may explain partly-contrasting findings of other studies where no long-term sampling was performed.

39

V 37 Using stable oxygen isotopes to assess vegetation impact on ecosystem water cycle and productivity in a Mediterranean oak woodland

M. Dubbert1, A. Piayda

2, F. Costa e Silva

3, A. Correia

3, J. Pereira

3, M. Cuntz

2, C. Werner

1

1Universität Bayreuth, Agrarökosystemforschung, Bayreuth, Deutschland

2Helmholtz Zentrum für Umweltforschung, Computational Hydrosystems, Leipzig, Deutschland

3Uiversidade Lisboa, Instituto Superior de Agronomia, Lisboa, Portugal

Water is one of the key factors driving ecosystem productivity, especially in water-limited ecosystems. Thus a separation of the component fluxes is needed to gain a functional understanding on the devel-opment of net ecosystem water and carbon fluxes. Oxygen isotope signatures are valuable tracers for such water movements within the ecosystem because of the distinct isotopic compositions of water in the soil and vegetation. In the past, determination of isotopic signatures of evaporative or transpirational fluxes has been challenging since measurements of water vapor isotopes were difficult to obtain using cold-trap methods. Recent developments in laser spectroscopy now enable direct high frequency measurements of the isotopic composition of atmospheric water vapor (δv), evapotranspira-tion (δET), and its components and allow validations of common modeling approaches for estimating δE

and δT based on Craig and Gordon (1965).

Here, a novel approach was used, combining a custom build flow-through gas-exchange branch chamber with a Cavity Ring-Down Spectrometer in a Mediterranean cork-oak woodland where two vegetation layers respond differently to drought: oak-trees (Quercus suber L.) avoid drought due to their access to ground water while herbaceous plants survive the summer as seeds. We used this ap-proach to quantify the impact of the understory herbaceous vegetation on ecosystem carbon and wa-ter fluxes throughout the year and disentangle how ET components of the ecosystem relate to carbon dioxide exchange.

We present one year data set comparing modeled and measured stable oxygen isotope signatures (δ

18O) of soil evaporation, confirming that the Craig and Gordon equation leads to good agreement

with measured δ18

O of evaporation (Dubbert et al., 2013). Moreover, we found continuously strong de-viations from isotopic steady-state in plant transpiration (Dubbert et al., 2014). This implies that as-suming plant transpiration to be in the steady-state can have a huge impact for studies that distinguish relatively short time intervals (hours, e.g. partitioning studies). Finally. partitioning ecosystem ET and NEE into its three sources revealed that understory vegetation contributed markedly to ecosystem ET and gross primary production (GPP; max. 43 and 51%, respectively). It reached similar water-use effi-ciencies (WUE) as cork-oak trees and significantly contributed to the ecosystem sink-strength in spring and fall. The understory vegetation layer further strongly inhibited soil evaporation (E) and, although E was large during wet periods, it did not diminish ecosystem WUE during water-limited times.

Craig H, Gordon, LI. 1965. Deuterium and oxygen-18 variations in the ocean and the marine atmos-phere. Paper presented at the Stable Isotopes in Oceanographic Studies and Paleotemperatures, Spoleto, Italy.

Dubbert M, Cuntz M, Piayda A, Maguas C, Werner C, 2013: Partitioning evapotranspiration - Testing the Craig and Gordon model with field measurements of oxygen isotope ratios of evaporative fluxes. J Hydrol.

Dubbert M, Piayda A, Cuntz M, Werner C, 2014. Oxygen isotope signatures of transpired water vapor - the role of non-steady-state transpiration under natural conditions. New Phyt.

40

Anhang 1

Anhang 2

41

Poster

Session 1 – Analytik: Neue Methoden und Techniken

P 1 SPINMIMS eine Vereinfachung der SPINMAS Messtechnik zur online Messung der

15N-

Häufigkeiten in Ammonium, Nitrit und Nitrat

W. Eschenbach1, R. Well

1, F. Stange

2, A. Giesemann

1

1Thünen-Institut für Agrarklimaschutz, Braunschweig, Deutschland

2Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Deutschland

Gängige Methoden zur Messung der 15

N Häufigkeit in einzelnen N-Spezies wie NH4+, NO2

- und NO3

-

in Proben mit mehreren N-Spezies (z.B. die Diffusionsmethode) sind arbeitsintensiv und zeitaufwän-dig. Eine automatisierte, schnelle und selektive Bestimmung von

15N Häufigkeiten in NH4

+, NO2

- und

NO3- in wässrigen Proben ist durch die SPINMAS-Technik (Stange et al. 2007) möglich. Aufbauend

auf Arbeiten von Russow et al. (1996) und Russow (1999) wird je nach N-Spezies eine bestimmte Reaktionslösung in einer Probenpräparationseinheit für anorganische N-Spezies (SPIN) mit der Probe vermischt. Die gasförmigen Reaktionsprodukte werden dann im He-Strom zu einem Quadrupolmassenspektrometer (MAS) geleitet.

Durch die Verwendung eines Membraneinlass-Massenspektrometers (MIMS) kann der für die SPINMASS Technik benötigte instrumentelle Aufbau deutlich vereinfacht werden. Der hier vorgestellte SPINMIMS Ansatz beruht auf der Verwendung einer Reaktionskapillare, in der die Probe mit den zu analysierenden N-Spezies und der entsprechenden Reaktionslösung gemischt werden. Von dort wird die Analysenlösung direkt zum Membraneinlass gepumpt, von wo die bei der Umsetzung von NH4

+,

NO2- und NO3

- gebildeten Reaktionsprodukte (N2 und NO) durch eine semipermeable Membran direkt

in die Ionenquelle des Massenspektrometers geleitet werden.

15N Standards (NH4

+ und NO3

- jeweils in dest. Wasser) mit verschiedenen at%

15N wurden selbst er-

stellt und per IRMS Messungen die erwarteten 15

N Gehalte überprüft. Insgesamt zeigen die SPINMIMS-Messungen eine gute Übereinstimmung gemessener und erwarteter

15N Häufigkeiten

(Abweichung < 0,8 at% 15

N im Bereich von 1 - 99 at% 15

N für NH4+- und < 0,15 at%

15N im Bereich

von 0,6 - 10 at% 15

N für NO3--Standards). Bei hoch mit

15N angereicherten NO3

- Proben zeigt sich eine

zunehmende Abweichung zwischen Ergebnissen der SPINMIMS-Messungen und den Erwartungswer-ten. Modellierend konnte gezeigt werden, dass dies durch in der Ionenquelle gebildete

30N2 Fragmen-

te, von bei der NO3- Umsetzung vermutlich gebildetem N2O, erklärt werden könnte.

Referenzen:

Stange, C.F., Spott, O., Apelt, B. und Russow, R.W.B. (2007) Automated and rapid online determina-tion of

15N abundance and concentration of ammonium, nitrite, or nitrate in aqueous samples by the

SPINMAS technique. Isotopes in Environmental and Health Studies. 43, 227-236.

Russow, R. (1999) Determination of 15

N in 15

N-enriched nitrite and nitrate in aqueous samples by reac-tion continuous-flow quadrupole mass spectrometry. Rapid Communications in Mass Spectrometry, 13, 1334-1338.

Russow, R., Sich, I. und Stevens, R.J. (1996) rapid, sensitive and highly selective 15

N analysis of 15

N enriched nitrite in water samples and soil extracts by nitric oxide production and CF-QMS measure-ment. Isotopes in Environmental and Health Studies. 32, 323-328.

42

P 2 Compound-specific isotope analysis of glyphosate and its metabolite AMPA during degrada-tion

E. Mogusu1, M. Elsner

1, M. Jochmann

2, B. Wolbert

2

1Institute of groundwater ecology, Munich, Deutschland

2University of Duisburg-Essen, Instrumental Analytical Chemistry, Essen, Deutschland

Glyphosate (N-(phosphomethyl)-glycine) is a widely used herbicide in agricultural and landscape management. Glyphosate strongly adsorbs in soil and may be biodegraded by soil microorganisms giving AMPA (amino-methyl phosphoric acid) as main transformation product [1, 2]. Major research efforts have focused on assessing the environmental fate of glyphosate and its main metabolite AMPA which are frequently detected in surface and groundwater. To this end, concentration measurements alone are often not conclusive [3]. To advance an alternative approach, we (i) developed nitrogen sta-ble isotope analysis (

15N/

14N) of glyphosate and AMPA by derivatization-gas chromatography/ isotope

ratio mass spectrometry (GC/IRMS), Accurate δ15

N values were obtained (deviation from elemental analyzer-IRMS): 0.23‰ ± 0.88‰ for glyphosate and 0.37‰ ± 0.70‰ for AMPA [4]. We (ii) subse-quently used the method to investigate nitrogen isotope fractionation during transformation of glypho-sate at Manganese dioxide (MnO2) surfaces [5], where we observed enrichment factors as high as εN = -17‰ ±0.5‰. Finally, we (iii) isolated glyphosate-degrading bacteria from soil to investigate carbon isotope fractionation (measured with liquid chromatography-IRMS) during glyphosate biodegradation. We successfully isolated bacteria from soils collected at a glyphosate applied vineyard from northern France that showed the ability to degrade glyphosate as Phosphorous source similar to other studies [6, 7]. Only small carbon isotope fractionation was observed during biodegradation of glyphosate εC = -6 ‰ indicating that intrinsic fractionation may be masked. There is promising potential to use CSIA (compound-specific isotope analysis) to study the degradation of glyphosate and its metabolite AMPA

Key words: glyphosate, AMPA, GC-IRMS, LC-IRMS, CSIA

References

Helander, M.; Saloniemi, I.; Saikkonen, K. Trends in Plant Science, 2012, Vol. 17, No. 10

Borggaard, K. O.; Gimsing A. L. Pest Manag. Sci, 2008, 64:441-456

Imfeld, G,; M. Lefrancq, E.; Maillard, S.; Payraudeau. Chemosphere, (2012) 471-479

Mogusu,O.E.; Elsner, M.; Jochmann, M. A. (2014) to be submitted Anal. Bioanal. Chem, 2014

K.A, Barret, M.B. McBride. Environ. Sci. Technol. (2005), 9222-9228

Ermakova, I.; Kiseleva, N.; Shushkova, T.; Zharikov, M.; Zharikov, G.; Leontievsky, A.; Appl Microbial. Biotechnol. 2010, 88:585-594.

Sviridov , A.V.; Shushkova ,T. V.; Zelenkova, N.F.; Vinokurova , N.G.; Morgunov , I. G.I.; T. Ermakova, T.; Leontievsky, A.A. Appl. Microbiol. Biotechnol. 2012, 93:787-796.

43

P 3 Optimization of an isotope ratio mass spectrometer and a cryogenic CO2 extraction system for δ

13C(CO2) and δ

18O(CO2) analysis on air samples within the ICOS Infrastructure

M. Eritt1, A. Janoschka

1, D. Rzesanke

1, W. Brand

1

1MPI BGC Jena, Jena, Deutschland

An Isotope ratio mass spectrometer (IRMS, ThermoFischer MAT 253) for δ13

C(CO2) and δ18

O(CO2) analysis of small air samples (2 litre at 1.2bar) is currently under installation at the MPI-BGC Jena.

With our IRMS, the numbers of CO2 molecules with m/zs 44, 45 and 46 are measured simultaneously to calculate

13C/

12C and

18O/

16O ratios. CO2 measurements of dilute air samples become available uti-

lizing a CO2 cryo-trap technique, that was first developed at MPI-BGC in 2001[1]

. In order to achieve the WMO target compatibility criteria

[2] (Δδ

13C = 0.010‰, Δδ

18O = 0.050‰) extensive instrument tests

were made and subsequent setup improvements were implemented. We present results and conclusions from measurements taken during the optimization of the δ-measurement method, including:

- optimization of the signal stability at the Faraday cups

- characterization of the mass ratio stability including differences between reference and sample side

- observation of time delays after change over switching (η-effect)

- and optimization of the cryo-trap towards efficiency, long- time stability and general signal stability.

References

[1] R. A. Werner, M. Rothe, W. A. Brand, Rapid Communications in Mass Spectrometry 2001, 15, 2152.

[2] G. Brailsford, in WMO-GAW Report No. 206, Vol. 206 (Ed.: G. Brailsford), Wellington, 2012, pp. 1.

44

P 4 Einsatz eines CO2- Isotopenlasers im kontinuierlichen Betrieb an einer Mikrokosmenanlage zur Untersuchung von bodenökologischen Prozessen

S. Burkart1, K. Leiber-Sauheitl

1, A. Giesemann

1, R. Well

1

1Thünen-Institut für Agrarklimaschutz, Braunschweig, Deutschland

Zum Studium der Prozesse bei der Emission von Treibhausgasen aus Böden spielen Mikrokosmenanlagen eine große Rolle. Dazu werden Bodensäulen in Plexiglasbehältern (Mikrokosmen) unter klimatisierten Bedingungen mit synthetischer Luft kontrolliert. Aus der Abluft wird automatisch deren Gehalt an CO2, N2O und CH4 mittels Gaschromatographen bestimmt. Die Durch-flussrate der Luft durch die Säulen wird sequentiell an den einzelnen Säulen nacheinander gemessen und anhand einer Rückrechnung die Produktion dieser Gase in den Säulen bestimmt.

Über reine Konzentrationsmessungen hinaus werden im Rahmen der Untersuchung bodenökologi-scher Prozesse isotopisch markierte Substanzen eingesetzt. So werden z.B. den Böden

13C angerei-

cherte Substrate zugefügt um Umsetzungen, Verlagerung oder Sequestration des Kohlenstoffs zu un-tersuchen.

Eine Analyse der C -Isotopensignatur in den Abluftproben aus einem Mikrokosmenversuch, bei dem eine Vielzahl von Bodensäulen zum Einsatz kommen, ist mit klassischen Isotopenhäufigkeitsmassen-spektrometern sehr arbeitsaufwendig und zeitintensiv. Außerdem sind durch einzelne Probenahmen zu fixen Terminen immer nur diskontinuierlich punktuelle Momentaufnahmen möglich.

Mit einem Laser-Isotopenanalysator (Picarro G1101-i) kann direkt online in der Abluft aus den einzel-nen Bodensäulen die C-Isotopensignatur im CO2 gemessen werden. Hierfür werden - wie bei den Konzentrationsbestimmungen auch - nacheinander die d

13C Werte in der Säulenabluft gemessen.

Während die Flussraten durch die Säulen variieren können und meist bei 10 mL min-1

liegen, beträgt sie beim Picarro G1101-i jedoch 22 mL min

-1. Zur Lösung des Problems dieser Diskrepanz bieten sich

verschiedene Möglichkeiten an. Wenn die Flussrate durch die Säule geringer als die durch den Picarro ist, kann man den Picarro über ein T-Stück und ein Nadelventil zur Flussverringerung hinter den Flussmesser anschließen. Dies wird zwangsläufig zu einer deutlichen Verlängerung der Ansprechzeit führen. Bei ausreichend hoher CO2-Konzentration kann man die Abluft mit einem Make-Up-Gas verdünnen, um ein Nadelventil zu vermeiden. Eine kürzere Ansprechzeit kann aber auch durch Integration des Picarro in einen Loop erreicht wer-den. Die Vakuumpumpe des Gerätes weist jedoch eine bauartbedingte Undichtigkeit auf.

Die Koppelung des Picarro an die im Thünen-Institut für Agrarklimaschutz vorhandene Mikrokosmenanlage wurde erstmals für einen Versuch mit Moorböden eingesetzt, bei dem der Ver-bleib des Kohlenstoffs aus

13C markiertem Schafskot und -urin untersucht wurde. Wir haben die oben

erwähnten Anschlussoptionen mit dem Moorbodenexperiment, aber auch mit Gasmischungen mit ver-schiedenen d

13C Werten getestet im Hinblick auf ein optimales Umschaltintervall zwischen den Säulen

bei guter Genauigkeit der gewonnenen Daten und stellen die Ergebnisse hier vor.

45

P 5 A preliminary refinement of the clumped isotope paleothermometer for biogenic apatite and an experimental approach for abiotic apatite

N. Löffler1, T. Rutz

1, U. Wacker

1, T. Tütken

2, A. Conrad

3, M. E. Böttcher

3, J. Fiebig

1,4

1Institute of Geosciences, Goethe-University, Frankfurt am Main, Deutschland

2Institute of Geosciences, Johannes Gutenberg-University, Mainz, Deutschland

3Department of Marine Geology, Leibniz-Institute for Baltic Sea Research, Warnemünde, Deutschland

4Biodiversity and Climate Research Center, Frankfurt am Main, Deutschland

Clumped isotope analysis of carbonates provides a new paleothermometer (Ghosh et al., 2006). The temperature dependence of the extent of

13C-

18O clumping (expressed as Δ47) inside carbonateshas

been investigated in several studies(e.g., Ghosh et al., 2006; Dennis and Schrag, 2010; Wacker et al. 2014), but little attentionwas paid to carbonate-bearing minerals, such asbiogenic and abiotic phos-phates. First investigations by Eagle et al. (2010) implied that bio-apatites may follow aT- dependencesimilar to thatproposed for calcite by Ghosh et al. (2006). However, it has remainedin doubtif the calibration of Ghosh et al. (2006) is accurate (e.g., Wacker et al. 2013, 2014).

The aim of this work is to create a refined calibrationfor biogenic and abiotic (authigenic) carbonate-bearing apatites. So far, teeth of a Greenland shark (Somniosus microcephalus, growth T ~2°C) and of an African elephant (Loxodonta africana, T ~ 37°C) have been analyzed for their clumped isotope compositions using phosphoric acid digestion temperatures of 90°C and 110 °C. These investigations imply that the evolved CO2 does not equilibrate inside the acidic environment. Enamel Δ47 seems to exhibit a T dependence that is very much different from results of Eagle et al. (2010), but much more similar to those of Wacker et al. (2014). Dentine, on the other hand, does not follow the T dependence of enamel. Reasons for the observed discrepancy between enamel and dentine will be discussed. Moreover, the clumped isotopic composition of enamel from a fossil tooth of C. megalodon has been analyzed to test the potential of the bioapatite clumped isotope thermometer for recording tempera-tures of the paleoocean and body temperatures of extinct vertebrates. Next, data from natural samples will be refined by measurements on abiotic samples prepared by different methods at T between 10°C and 60°C.

References

Dennis K. and Schrag D. (2010) Clumped isotope thermometry of carbonatites as an indicator of diagenetic alteration. Geochim. Cosmochim. Acta 74, 4110-4122.

Eagle R. A., Schauble E. A., Tripati A. K., Tütken T., Hulbert R. C., Eiler J. M. (2010) Body tempera-tures of modern and extinct vertebrates from

13C-

18O bond abundances in bioapatite. PNAS 107,

10377- 10382

Ghosh P., Adkins J., Affek H., Balta B., Guo W., Schauble E. A., Schrag D., Eiler J. M. (2006) 13

C-18

O bonds in carbonate minerals: A new kind of paleothermometer. Geochim. et Cosmochim. Acta 70, 1439-1456Wacker U., Fiebig J., Schoene B. R. (2013) Clumped isotope analysis of carbonates: com-parison of two different acid digestion techniques. Rapid Commun. Mass Spectrom. 27, 1631- 1642

Wacker U., Fiebig J., Schoene B. R. (2013) Clumped isotope analysis of carbonates: comparison of two different acid digestion techniques. Rapid Commun. Mass Spectrom. 27, 1631-1642

Wacker U., Fiebig J., Tödter J., Schöne B. R., Bahr A., Friedrich O., Tütken T., Gischler E., Joachimski M. M. (2014) Empirical calibration of the clumped isotope paleothermometer using calcites of various origins. Geochim. et Cosmochim. Acta 141, 127-144

46

P 6 Progress in compound-specific oxygen isotope analysis of sugars

M. M. Lehmann1, M. Fischer

2, M. Zech

3, R. T. W. Siegwolf

1, M. Saurer

1

1Paul Scherrer Institute (PSI), Laboratory of Atmospheric Chemistry, Villigen, Schweiz

2Empa, Laboratory for Nanoscale Materials Science, Dübendorf, Schweiz

3Universität Bayreuth, Bodenphysik & Lehrstuhl für Geomorphologie, Bayreuth, Deutschland

Determination of the oxygen isotope ratio (δ18O) of plant material has been widely used under con-trolled and field conditions to investigate biochemical and physiological isotope effects. As a result, de-tailed models describing fractionation processes in leaves have been developed. This enabled the use of δ18O analysis of tree-ring cellulose as a biomarker for plant physiological and climatic studies. Nowadays, methods for bulk analysis of δ18O of total soluble carbohydrates and stem cellulose are well established, while applicable methods are still missing for δ18O analysis of sugars as main pre-cursor of cellulose. This is crucial due to the fact that δ18O of individual sugars hold potential infor-mation about detailed biochemical processes, which cannot be disentangled with bulk analysis, for in-stance, about the importance of mixing of different compounds, the exchange of carbonyl groups with water, and the impact of δ18O of sucrose on stem cellulose. Therefore, current methods for com-pound-specific oxygen isotope analysis (CSIA) of sugars should be improved or new methods estab-lished. CSIA measurements with GC-IRMS pyrolysis are still a great challenge and only very few data exist so far. Recently, we have developed a method using tri-methylsilylation derivatization to analyze δ18O of sugars with GC-IRMS, with good results for sucrose (Zech et al., 2013). In a next step, we applied a novel method by using methylation derivatization, which led to more accurate results for su-crose than with tri-methylsilylation, but also to acceptable results for fructose and glucose, which could not be measured before. This new method promises to be a big step forward in analyzing δ18O of sugars.In future we want (1) to improve the precision of the method to analyze δ18O of sugars at natu-ral abundance; (2) to make the method applicable also for other important sugars (galactose, raffinose) and sugar-alcohols (pinitol and myo-inositol); and (3) to apply this method to samples of field campaigns and of experiments performed under controlled conditions. Finally, we aim to provide a novel and easy to use method for δ18O analysis of sugars for wide-spread applications in diverse re-search fields.

Zech M, Saurer M, Tuthorn M, Rinne KT, Werner RA, Siegwolf RTW, Glaser B, Juchelka D. 2013. A novel methodological approach for δ18O analysis of sugars using gas chromatography-pyrolysis-isotope ratio mass spectrometry. Isotopes in Environmental and Health Studies 49: 492-502.

47

P 7 Pitfalls in nitrate isotope analysis and how to avoid them

E. Ryabenko1, M. Stoewer

1, K. Knoeller

2, M. Elsner

1, F. Buegger

3

1Helmholtz Zentrum München, Institute of Groundwater Ecology, Neuherberg, Deutschland

2Helmholtz-Centre for Environmental Research, Halle, Deutschland

3Helmholtz Zentrum München, Institute for Soil Ecology, Neuherberg, Deutschland

Nitrogen (δ15

N) and oxygen (δ18

O) isotope ratios of nitrate (NO3-) are often used to trace dominant

NO3- pollution sources in water. Three methods are currently employed: (i) the silver nitrate (AgNO3)

method, (ii) the bacterial denitrification method and (iii) the cadmium reduction method. The AgNO3 method is not applicable to saline samples and requires comparatively high concentrations of NO3

-

(100-200 mmol), because it relies on NO3- purification by anion-exchange and subsequent precipita-

tion as AgNO3, for analysis by elemental analyser-isotope ratio mass spectrometry (EA-IRMS). The existence of large blanks from dissolved organic matter can also be an issue in the application of this method. The bacterial denitrification method uses bacteria to convert NO3

- into N2O [1] and the cadmi-

um method produces N2O by chemical reduction of NO3- to NO2

- with a subsequent reaction with azide

[2]. Since the formation of N2O eliminates any interferences and is amenable to gas chromatography-IRMS, the two “N2O methods” have a detection limit below 1 µmol and can also be used for seawater samples. Despite these advantages, the N2O methods are not yet universally adapted and a reliable method comparison is still missing.

Here we present a first systematic comparison of all three methods: the most typical pitfalls for each of these methods, starting from sample collection and preservation into method’s application for isotope analysis. In the near future, we plan to compare these methods using river-, ground- and contaminated water samples having a wide range of δ

15N- and δ

18O-NO3

-values and NO3

- concentrations.

1. Sigman et al. (2001) Anal. Chem. 73, 4145-4153

2. Ryabenko et al.(2009) L&O-Methods 7, 545-552

48

P 8 Inter-laboratory assessment of nitrous oxide isotopomer analysis by isotope ratio mass spectrometry and laser spectroscopy: current status and perspectives

J. Mohn1, B. Wolf

1,2, S. Toyoda

3, C.- T. Lin

4, M.- C. Liang

4,5, N. Brüggemann

6, H. Wissel

6,

A. E. Steiker7, J. Dyckmans

8, L. Szwec

8, N. E. Ostrom

9, K. Casciotti

10, M. Forbes

10, A. Giesemann

11,

R. Well11

, R. R. Doucett12

, C. T. Yarnes12

, A. R. Ridley13

, J. Kaiser13

, N. Yoshida3

1Empa, Dübendorf, Deutschland

2Karlsruhe Institute of Technology, Garmisch-Partenkirchen, Deutschland

3Tokyo Institute of Technology, Tokyo, Japan

4Academia Sinica, Taiwan, Taiwan

5National Central University, Taiwan, Taiwan

6Forschungszentrum, Jülich, Deutschland

7University of Colorado, Colorado, Vereinigte Staaten von Amerika

8Georg-August University, Göttingen, Deutschland

9Michigan State University, Michigan, Vereinigte Staaten von Amerika

10Stanford University, Stanford, Vereinigte Staaten von Amerika

11Johann Heinrich von Thünen Institut, Braunschweig, Deutschland

12University of California, Davis, Vereinigte Staaten von Amerika

13University of East Anglia, Norwich, Großbritannien

In recent years, research and applications of the N2O site-specific nitrogen isotope composition have advanced [Toyoda et al., 2013], reflecting awareness of the contribution of N2O to the anthropogenic greenhouse effect, and leading to significant progress in instrument development [Wächter et al., 2008, Mohn et al., 2012]. Further dissemination of N2O isotopomer analysis, however, is hampered by a lack of internationally agreed gaseous N2O reference materials and an uncertain compatibility of dif-ferent laboratories and analytical techniques [Köster at al., 2013, Park et al., 2012].

In a first comparison approach, eleven laboratories were each provided with N2O at tropospheric mole fractions (target gas T) and two reference gases (S1 and S2). The laboratories analyzed all gases, applying their specific analytical routines. Compatibility of laboratories was assessed based on N2O isotopocule data for T, S1 and S2. Results for the T were then standardized using S1 and S2 to eval-uate the potential of N2O reference materials for improving compatibility between laboratories.

Compatibility between laboratories depended on the analytical technique: isotope ratio mass spec-trometry (IRMS) results showed better compatibility for d

15N while the performance of laser spectros-

copy was superior with respect to N2O site preference. This comparison, however, is restricted by the small number of participating laboratories applying laser spectroscopy. Offset and two-point calibration correction of the N2O isotopomer data significantly improved the consistency of position-dependent nitrogen isotope data while the effect on d

15N was only minor.

The study reveals that for future research on N2O isotopocules, standardization against N2O reference material is essential to improve interlaboratory compatibility. For atmospheric monitoring activities, we suggest N2O in whole air as a unifying scale anchor.

References

Toyoda, S., N. Kuroki, N. Yoshida, K. Ishijima, Y. Tohjima, and T. Machida (2013), Decadal time se-ries of tropospheric abundance of N2O isotopomers and isotopologues in the Northern Hemisphere obtained by the long-term observation at Hateruma Island, Japan, J. Geophys. Res., 118, 3369-3381, doi: 10.1002/jgrd.50221.

Wächter, H., J. Mohn, B. Tuzson, L. Emmenegger, and M. W. Sigrist (2008), Determination of N2O isotopomers with quantum cascade laser based absorption spectroscopy, Opt. Express, 16 (12), 9239-9244, doi: 10.1364/OE.16.009239.

Mohn, J., B. Tuzson, A. Manninen, N. Yoshida, S. Toyoda, W. A. Brand, L. Emmenegger (2012), Site selective real-time measurements of atmospheric N2O isotopomers by laser spectroscopy, Atmos. Meas. Tech., 5, 1601-1609, doi: 10.5194/amt-5-1601-2012.

49

Köster, J. R., R. Well, B. Tuzson, R. Bol, K. Dittert, A. Giesemann, L. Emmenegger, A. Manninen, L. Cárdenas, and J. Mohn (2013), Novel laser spectroscopic technique for continuous analysis of N2O isotopomers-Application and intercomparison with isotope ratio mass spectrometry, Rapid Commun. Mass Spectrom., 27 (1), 216-222, doi: 10.1002/rcm.6434.

Park, S., P. Croteau, K. A. Boering, D. M. Etheridge, D. Ferretti, P. J. Fraser, K. R. Kim, P. B. Krummel, R. L. Langenfelds, T. D. Van Ommen, L. P. Steele, C. M. Trudinger (2012), Trends and seasonal cycles in the isotopic composition of nitrous oxide since 1940, Nat. Geosci., 5 (4), 261-265, doi: 10.1038/ngeo1421.

50

P 9 Real-time measurements of nitrous oxide isotopomers at a tall tower: Identifying sources and hot spots in Switzerland

E. Gute1, E. Harris

1, B. Tuzson

1, L. Emmenegger

1, J. Mohn

1

1Empa, Dübendorf, Schweiz

Atmospheric N2O mixing ratios have been rising at a rate of 0.2-0.3% per year over the past decades due to enhanced microbial production in fertilized agricultural soils. N2O sources are linked to different microbial processes occurring in soils, therefore sources are disperse and highly variable, complicat-ing the development of effective mitigation strategies. Isotopic measurements have great potential to unravel spatial and temporal variations in sources and processes of N2O. Recent developments in quantum cascade laser spectroscopy coupled to automated N2O preconcentration (Mohn et al. 2012; Harris et al. 2014; Wolf et al. 2014) allow both the intermolecular distribution of

15N substitutions (‘site

preference’; 15

N14

N16

O versus 14

N15

N16

O) and the oxygen isotopic composition (δ18

O) of N2O to be measured with a precision of-1.

In this study, the performance of the laser-based measurement technique is further improved with re-spect to temporal resolution, accuracy and long-term precision for operation under field conditions. A special focus will be placed on the temperature stabilization of the spectrometer, removal of trace gas interferences, and anchoring of the measurement results (delta values and mixing ratios) to interna-tional standard scales. The foreseen real-time measurements of N2O mixing ratios and site-specific isotopic composition at a tall tower in Central Switzerland (Beromünster), in combination with back-ward Lagrangian particle dispersion modelling and an inversion system, will then be applied to deter-mine source strengths and their isotopic composition in Northern Switzerland.

References

Harris, E., Nelson, D., Olszewski, W., Zahniser, M., Potter, K., McManus, B., Whitehill, A., Prinn, R., Ono, S. (2014) Development of a Spectroscopic Technique for Continuous Online Monitoring of Oxy-gen and Site-Specific Nitrogen Isotopic Composition of Atmospheric Nitrous Oxide. Analytical Chemis-try Articles ASAP, doi: 10.1021/ac403606u.

Mohn, J., Tuzson, B., Manninen, A., Yoshida, N., Toyoda, S., Brand, W.A., Emmenegger, L. (2012) Site selective real-time measurements of atmospheric N2O isotopomers by laser spectroscopy. At-mospheric Measurement Techniques 5: 1601-1609.

B. Wolf, B. Tuzson, L. Merbold, C. Decock, L. Emmenegger, J. Mohn, in EGU General Assembly, vol. 16. Geophysical Research Abstracts, Vienna, 2014.

51

P 10 Investigation of the isotopic fractionation during direct photolysis of Sulfamethoxazol

J.- B. Wolbert1, D. M. Kujawinski

1, M. A. Jochmann

1, T. C. Schmidt

1

1Universität Duisburg-Essen, IAC, Essen, Deutschland

Sulfonamides and their antimicrobial properties are already known since 1908 [1]. In contrast to herbi-cides andveterinarydrugs the environmental aspects were not important for theaccreditationtill 2003 [2]. In the meantime, numerous studies of the effects of drug residuals in water samples were per-formed, including sulfamethoxazole, one of the most usedantibiotics[3-5]. Although photolysis is the dominant transformation pathway of sulfamethoxazole in surface waters its degradation mechanism was not investigated by using stable isotope analysis.

Since transformations can be associated with isotope effects, the analysis of stable isotope composi-tions (δ

13C) of the reactant offers a possibility to obtain information about the degradation process

without the need for detecting specific degradation products.

The aim of this work was to develop a method to determine compound-specific carbon isotope analy-sis of sulfamethoxazole and its photolytic degradation products by High Temperature Liquid Chroma-tography Isotope Ratio Mass Spectrometry (HT-LC-IRMS), which allows monitoring of environmental degradation processes in surface waters. This method was applied to study the direct photolysis of sulfamethoxazole. The monitoring of the degradation by HT-LC-IRMS has been carried out by the use of an X-Bridge C18 (Waters, 3.5 µm particle size, 100 × 2.1 mm) chromatographic column and an elu-ent of pure water (50%) mixed with a phosphate buffer (50%, 10 mM, pH 3). The calculated carbon isotopic enrichment factor for the direct photolysis of sulfamethoxazole was very low with a value of 0.7 ± 0.1 ‰. Since no carbon bonds are broken only secondary isotopic effects cause a fractionation.

Literature

[1] Lesch, J., The first miracle drugs. 2006: Oxford University Press.

[2] Rönnefahrt, I., Koschorrek, J., Kolossa-Gehring, M., Mitteilungsblatt der Fachgruppe Umweltche-mie und Ökotoxikologie. , 2002. 8 (4).

[3] Mouamfon, M.V.N., Wenzhen, L., Shuguang, L., Zhaofu, Q., Nuo, C. Kuangfei, L., Environmental Technology, 2010, 31: 489-494.

[4] Boreen, A.L., W.A. Arnold, and K. McNeill, Environmental Science & Technology, 2004, 38: 3933-3940.

[5] Zhou, W. and D.E. Moore, International Journal of Pharmaceutics, 1994, 110: 55-63.

52

P 11 Validierung und Optimierung von Probenpräparationsmethoden für die d

15N-NH4-Analytik an

Wasser- und Bodenproben

D. Burghardt1, P. Baumann

1

1TU Dresden, Institut für Grundwasserwirtschaft, Dresden, Deutschland

Gegenstand einer ersten Studienarbeit zur d15N-NH4-Isotopenanalytik am Institut für Grundwasser-wirtschaft (Baumann, 2014) war die vergleichende Prüfung und Optimierung von Diffusionsmethoden, die bisher publiziert wurden.

Für die Aufbereitung von Wasserproben konnten dabei gute Ergebnisse mit einer Modifikation der Me-thode von (Sebilio et al., 2004) erzielt werden. Es konnten wertvolle Erkenntnisse zu den wichtigsten Voraussetzungen für eine vollständige und fraktionierungsfreien d15N-NH4- Analytik gewonnen wer-den, die die Basis weiterer Untersuchungen bilden werden.

Die modifizierte d15N-NH4-Probenvorbereitungsmethode konnte zudem erfolgreich an Grundwasser-proben aus dem Berliner Urstromtal validiert werden, die im An- und Abstrom einer in-situ- Grundwas-sersanierungsmaßnahme zur Stimulation der Nitrifikation eines NH4-Schadens entnommen wurden.

Weiterhin wurden erste Tests von in der Literatur beschriebenen Methoden durchgeführt, die sich der Präparation von NH4 zur d15N-Analytik widmen, welches in Bodenproben in kationenaustauschbar oder organisch gebundener Form vorliegt (z.B. Sorensen und Jensen, 1991, Carter und Gregorich, 2007). Hier konnten jedoch bisher keine zufriedenstellenden Ergebnisse erzielt werden.

53

P 12 Optimization of sample preparation procedure for Cl DI-IRMS measurement of organochlorines.

N. Ivdra1,2

, T. Gilevska2, M. Bonifacie

3, H. Eisenmann

1, H.- H. Richnow

2

1Isodetect GmbH, Leipzig, Deutschland

2Helmholtz Centre for Environmental Research - UFZ, Department of Isotope Biogeochemistry,

Leipzig, Deutschland 3Institut de Physique du Globe de Paris, Equipe de Géochimie des Isotopes Stables, Paris, Frankreich

The study aimed to optimize the analytical method to determine chlorine stable isotope composition (δ

37Cl) of γ-Hexachlorocyclohexane (γ-HCH) by Dual-Inlet Isotope Ratio Mass Spectrometry (DI-

IRMS). Sample preparation method, reported by Jendrzejewski et al.1 and Holmstrand et al.

2, included

sealed-tube combustion of organochlorine, followed by precipitation and subsequent conversion of formed inorganic chlorides to methyl chloride (CH3Cl). We identified the most critical step - dissolution of inorganic copper chlorides, formed by combustion of g-HCH. We found that significant amount of chlorine was trapped in undissolved CuCln, leading to changes in δ

37Cl (with preferential trapping of

heavy isotopes into Cu35

Cln). We have optimized the dissolution step to minimize losses of 35

Cl. We have tested the accuracy of the optimized method by analyzing CH3Cl sample with known δ

37Cl value

reported vs. the SMOC scale (Standard Mean Ocean Chloride) before and after the whole procedure. The difference between product and initial CH3Cl was 0.11 ± 0.04 ‰. Moreover, our optimized method is suitable for the broad range of chlorinated organic compounds, as the most critical step is not relat-ed to the chemical structure of the starting material.

References:

1. Jendrzejewski N., Eggenkamp H.G.M., Coleman M.L. Appl. Geochem., 2001, 16(9-10), 1021-1031.

2. Holmstrand H., Andersson P., Gustafsson O. Anal. Chem., 2004, 76(8), 2336-2342.

Acknowledgements:

1. Hans Eggenkamp, Kristina Hitzfeld, Thomas Giunta, Gerard Bardoux

2. Financial support by the European Union under FP7- People-ITN-2010 (Grant Agreement No. 264329)

54

P 13 Recharge estimation in a semi-arid environment using stable isotope methods: A discussion on in-situ field and laboratory techniques.

M. Gaj1, M. Beyer

1, P. Königer

1, Y. Hamutoko

2, H. Wanke

2, C. Kuells

3, T. Himmelsbach

1

1BGR, Hannover, Deutschland

2UNAM, Windhoek, Deutschland

3Fachhochschule, Lübeck, Deutschland

Stable Isotopes of water are useful proxies for the description of water fluxes such as infiltration, evapotranspiration and plant water uptake in natural water resource systems. Especially the meas-urement of soil pore water provides information of soil hydraulic properties and interactions within the soil-plant-atmosphere-interface. To obtain such information advanced techniques are required to ei-ther extract soil pore water or to equilibrate the soil sample with dry gas at fixed temperature. It is not yet fully understood to what extent different methods affect the isotope composition and how results of these compare to each other.

The present study compares direct in situ measurements using a hydrophobic poly-propylene mem-brane installed at various depths in the soil. The isotopic composition of the soil water vapor was measured with a Los Gatos research DLT-100 spectroanalyser directly in the field. Additional soil physical parameters such as temperature, soil moisture and suction tension were also measured in field and additionally grain sizes in the lab.

It could be observed that suction tension was strongly related to the diurnal temperature cycle for a sandy soil. The upper 10cm show a development of filaments which have hydrophobic properties. Re-sults of the in situ measurement indicate differences compared to the values derived from cryogenic vacuum extraction. For the upper soil layer results of the two diverge unexpectedly providing heavier values for the in situ measurements. Deuterium excess for the upper 20 cm plots parallel to the GMWL . The lower part of the soil plot with a slope between 3 and 4 in a 18O-2H diagram. Advances and pit-falls of field and laboratory techniques are discussed.

55

P 14 Performance of a laser based CO2 Isotope Ratio Infrared Spectrometer to study biosphere-atmosphere exchange

H. Jost1, E. Wapelhorst

2, H.- J. Schlueter

2, O. Kracht

2, J. Radke

2, A. Hilkert

2, L. Gangi

3, R. Bol

3,

C. van Leeuwen4, H. Meijer

4

1Thermo Fisher Scientific, Reinach, Schweiz

2Thermo Fisher Scientific, Bremen, Deutschland

3Forschungszentrum Jülich, Jülich, Deutschland

4Rijksuniversiteit, Groningen, Niederlande

We are presenting results from a mid-infrared laser-based Isotope Ratio Infrared Spectrometers (IRIS) that is capable of simultaneously determining both δ

18O and δ

13C isotope ratios of carbon dioxide uti-

lizing a simple, direct absorption approach with a robust multi pass cell and a cryogen free setup.

A simulation of ambient measurement conditions with a 75 ppm/hour change in CO2 concentration from 350-650 ppm showed a precision of <0.05‰ for both δ

18O and δ

13C over 24 hours with 30 min

averaging time. Comparison with Isotope Ratio Mass Spectrometer (IRMS) showed differences of 0.046 ‰ and 0.047 ‰, for δ

13C and δ

18O, respectively.

In a plant chamber simulation, the concentration ramp speed was increased up to 40 ppm/min. For 1 minute averaged samples, the precision was δ

13C = 0.097 ‰ and δ

18O = 0.121 ‰. The comparison

with IRMS gave a difference of 0.032 ‰ for δ13

C and 0.008 ‰ for δ18

O.

An example of ambient air monitoring over 2 weeks shows periods of advected urban pollution with increasing CO2 concentration as well as local photosynthetic activity that results in a draw down of the CO2 concentration and corresponding more positive δ

13C.

The IRIS analyzer was also integrated into a large plant chamber experiment involving multiple in-struments to study CO2 fluxes using δ

18O-CO2. Plant chamber in and out was alternatingly monitored

for 5 minutes. A comparison of δ18

O with a TGA-200 gave a mean difference Δδ18

O = -0.49 ‰ +- 0.37 ‰.

56

Poster

Session 2 – Hydrologie und Hydrogeologie

P 15 The oxygen and hydrogen isotope composition of precipitation and surface waters in North Germany

M. E. Böttcher1, E. O. Böttcher

2, T. M. C. Böttcher

3, M. Lipka

1, V. Winde

1, I. Schmiedinger

1

1Leibniz IOW, Geochemie & Isotopengeochemie, Warnemünde, Deutschland

221339, Lüneburg, Deutschland

326129, Oldenburg, Deutschland

The hydrological cycle is reflected by specific water isotope signatures found in precipitation, surface, and ground waters (Dansgaard, 1964; Craig & Gordon, 1965; Gat, 1996). Since fresh waters of differ-ent generation and ages may enter the coastal areas it is expected that they carry characteristic stable isotope signatures. Informations about the specific composition of different fresh water sources allows for a use in mixing models for the origin of coastal waters. Traditionally, investigations focused on the fractionation of the isotopes H-1, H-2, O-16, and O-18. With the development of new analytical meth-ods, also the O-17 isotope came into the focus of interest (Angert et al., 2004; Luz & Barkan, 2010).

We investigated the multi-isotope composition of different sources for fresh waters at sites with rele-vance for the southern coastal North and Baltic Sea areas (precipitation, river waters, coastal wells, coastal beach springs, fresh waters emerging from coastal marine sediments (SGD)). The composition of precipitation (rain, snow) at different locations in Northern Germany (Lüneburg, Oldenburg, Warnemünde) and the Netherlands (Texel Island) was analyzed to derive local meteoric water lines. Stable isotope measurements were conducted by means of a new Picarro CRDS system (L2140-i) giving results in the usual delta-notation versus V-SMOW, and informations about H-2 and O-17 ex-cess. Results are compared to continuous measurements at the GNIP station in Cuxhaven (NW-Germany) and the GMWL. As an example, measurements in the towns Lüneburg and Oldenburg for the time period between December 2013 and June 2014 are represented by the respective non-amount-weighted correlation equations (updating an earlier report based on a shorter observation pe-riod; Böttcher et al., 2014):

δ2H = 8.20*δ

18O + 10.75 (n =75; r

2 = 0.99),

and

δ2H = 7.62*δ

18O + 5.87 (n = 82; r

2 = 0.95).

Acknowledgements: Research was supported by BMBF within the AMBER and BIOACID projects, and Leibniz IOW

References: Böttcher M.E., Lipka M., Winde V., Dellwig O., Böttcher E.O., Böttcher T.M.C., Schmiedinger I.

(2014)

Multi-isotope composition of freshwater sources for the southern North and Baltic Sea. Proc. 23rd SWIM conference, Husum, 46-49 Angert, A., C.D. Cappa, D.J. de Paolo. 2004. Kinetic

17O effects in the hydrological cycle: Indirect evi-

dence and implications. Geochimica et Cosmochimica Acta, no.68: 3487-3495. Craig, H., and L.I. Gordon. 1965. Deuterium and oxygen-18 variations in the ocean and the marine atmosphere. In: Stable Isotopes in Oceanographic Studies and Paleotemperatures (ed. Tongiorgi, E.). 9-130, Laboratory of Geology and Nuclear Science. Dansgaard, W. 1964. Stable isotopes in precipitation. Tellus, no.16: 436-468. Gat, J.R. 1996. Oxygen and hydrogen isotopes in the hydrological cycle. Annual Reviews in Earth and Planetary Sciences, no.24: 225-262. Luz, B., and E. Barkan. 2010. Variations of

17O/

16O and

18O/

16O in meteoric waters. Geochimica et

Cosmochimica Acta, no.74: 6276-6286.

57

P 16 Ground waters emerging at the southern Baltic Sea coast: A multi-isotope hydrobiogeochemical study

M. Lipka1, J. Sültenfuß

2, Z. Wu

1, P. Escher

1, I. Schmiedinger

1, U. Struck

3, O. Dellwig

1, V. Winde

1,

M. E. Böttcher1

1Leibniz Institute for Baltic Sea Research Warnemuende, Geochemistry & Isotope Geochemistry,

Rostock, Deutschland 2University of Bremen, Environmental Physics Department, Bremen, Deutschland

3Natural History Museum, Stable Isotope Facilities, Berlin, Deutschland

Iron-rich groundwater springs emerging at the shore zone of the southern Baltic Sea (close to Kühlungsborn) were examined on a seasonal base for a period of about three years. Water samples were analyzed for major and trace elements, stable isotopes of water (

2H,

18O), tritium (

3H) and noble

gases (3He,

4He, Ne), DIC,

13C, and

34SO4. Sediment from the stream beds was characterized via

SEM-EDX and extracted for the geochemistry of authigenic precipitates.

The springs emerge from small pits yielding discharges close to 10 L/min. Surrounding sediments are sandy with gravels found at depth and corresponding high permeabilities. The positions of different springs on the shore zone were stable during the investigation period while their shape varied due to wind- and wave-driven forces. The

2H and

18O contents of the spring waters indicate the ground water

to originate from relatively young mixed meteoric waters. Dating using the tritium-helium method yields ages of the emerging waters of 25 to 32 years, with different mixing proportions of tritium-free waters. The hydrochemistry of the springs showed some variability in between, which indicates that the genet-ic processes might differ slightly. The springs are characterized by dissolved Ca, Mg, Na, DIC, and SO4 mainly reflecting the interaction with bedrocks in the recharge area that is dominated by marly till. The oxygen-free ground water is rich in dissolved Fe, P, and DIC. Fe and SO4 originate from the oxi-dation of pyrite, as shown by the

34S content in SO4. The isotope signature of DIC indicates the disso-

lution of biogenic CO2 in the soil zone followed by the dissolution of carbonate minerals. The above ground draining streams degas carbon dioxide and take up oxygen in contact with the atmosphere. Upon CO2-degassing,

12C is preferentially desorbed from the aqueous solution.

The water then passes to underground drainage into a subterranean mixing zone with brackish Baltic Sea waters. Iron(oxyhydr)oxide precipitates in the stream beds acting as a sink for dissolved PO4 and minor Ca. Residues of iron oxidizing bacteria were found in the stream bed rust indicating an involve-ment of microbes to catalyse the dissolved iron removal. The investigation reveals that the surface precipitation on the beach leads to the formation of submarine groundwater discharge essentially free of dissolved Fe and PO4. The formation of Fe-phases in the subterranean estuary is supposed at depth influencing the release of nutrients and metals into the coastal ecosystem.

Acknowledgements: This work was partly supported by the BONUS+ project AMBER and the Leibniz

IOW.

58

P 17 Determination of flow velocities by stable isotope geochemical methods

R. van Geldern1, A. Kolb

2, J. Barth

1

1FAU Erlangen-Nürnberg, GeoZentrum Nordbayern, Erlangen, Deutschland

2Bayerisches Landesamt für Umwelt (LfU), Dienststelle Wielenbach, Deutschland

Drinking water is often extracted from wells close to rivers and streams. Such bank filtrates may even-tually be impacted by the infiltration of wastewater-derived micro-pollutants from surface waters. It therefore essential to know the flow velocity, i.e. the effective fluid velocity a conservative tracer would experience during its flow from the river towards the well group. Hydrogen and oxygen stable isotope of water proved to be excellent tracers to determine the pathway of the water molecule in numerous studies.

In the context of the research program RISK-IDENT that focus on the identification, and fate and be-havior of micro pollutants in the environment we determined the fluid velocity by stable isotopes with-out the need of adding artificial tracers. The results of the stable isotope geochemical approach indi-cate a velocity of 2.9 m per day, which results in an average time of 50 days that is needed by a water molecule from the river to the drinking water well.

59

P 18 Tracing nitrate sources in pre-alpine groundwater catchments using environmental tracers

M. Stoewer1, K. Knöller

2, C. Stumpp

1

1Helmholtz Zentrum München, Grundwasserökologie, Hydrogeologie, Neuherberg, Deutschland

2Helmholtz Center for Environmental Research, Department of Catchment Hydrology - Stable Isotope

Group, Halle a. Saale, Deutschland

Groundwater is one of the main resources for drinking water. Its quality is still threatened by the ubiq-uitous contaminant nitrate (NO3

-). In order to manage groundwater resources in a sustainable manner,

we need to find options of lowering nitrate input. Thus, a comprehensive knowledge of nitrate sources and time scales of transport are required. The objectives of the present study were to i) identify major sources of nitrate in groundwater and ii) investigate seasonal dynamics of nitrogen-compounds in oli-gotrophic aquifers. To achieve the objectives, we applied environmental tracer approaches in four pre-alpine groundwater catchments. Stable isotopes of water and tritium were used to study the hydroge-ology and transit times. Furthermore, nitrate isotopes were applied to trace nitrogen from its sources to groundwater. The results of the nitrate isotope analysis showed that groundwater nitrate derived from ammonium nitrification from a variety of sources such as atmospheric deposition, mineral and organic fertilizers and soil organic matter. A direct influence of mineral fertilizer, atmospheric deposition and sewage were excluded. Since seasonal variations in stable isotopes of nitrate were detected only in surface water and locally at one groundwater monitoring well, aquifers appeared to be well mixed and influenced by a continuous nitrate input mainly from soil derived nitrogen. Hydrogeological analysis supported that the investigated aquifers were less vulnerable to rapid impacts due to long average transit times, ranging from five to 21 years. Our study revealed the importance of combining environ-mental tracer approaches and a comprehensive sampling campaign (local sources of nitrate, soil wa-ter, river water, and groundwater) to identify the nitrate sources in groundwater and its vulnerability. In the future, the achieved results will help develop targeted strategies for a sustainable groundwater management focusing more on soil nitrogen storage.

60

P 19 Isotope signatures to trace the origin and fate of nitrate in the Soyang Lake Watershed, South Korea

S. Parra Suarez1, G. Gebauer

1

1 BayCEER – Laboratory of Isotope Biogeochemistry University of Bayreuth, Bayreuth, Deutschland

The Monsoon season in South Korea has a great influence on the biogeochemical and hydrological processes in the entire country, but is specifically of concern in the Soyang Lake Watershed, the main drinking water reservoir for the 20 million metropolis Seoul. The Soyang Lake Watershed is composed of sub-catchments dominated by intensive agricultural management, and by pristine (semi-) natural broadleaf and coniferous forests. Therefore nitrate leaching into surface waters may have different ori-gins. Stable isotopes are a useful tool to quantify and determinate the origin of nitrate inputs into the Soyang Lake. The δ15N values of nitrate from different sources often show overlapping ranges but the additional measurement of the δ18O values allows a more precise classification (Durka et al., 1993; Mayer et al., 2002; Deutsch et al. 2006). The δ18O values of NO3- are especially useful for differenti-ating between NO3- deposited from the atmosphere and NO3- formed by microbial nitrification. The formation of NO3- in the atmosphere involves exchange of oxygen atoms with ozone which has a high δ18O value (Curtis et al 2011). In contrast NO3- formed by microbial nitrification derives most of its oxygen from water which has a lower δ18O value. (Curtis et al 2011). According with this principle the nitrate derive from sewage or manure or fertilizes is isotopically distinct between each other and from the other sources. Within a sampling along the rivers and in the land around them, with a frequency ranging from one time after each rain event to every two hours, the sampling design was made to determinate the influ-ence of the precipitation regime and the land use in the nitrate discharge into the Soyang Lake Water-shed. River water samples, soil water samples and rain samples were taken before and during the monsoon season to analyse the nitrate concentration and 15N abundance in each phase of the nitro-gen cycle. Data from amount of rain and river discharge were taken to quantify the total export of ni-trate from these sub-catchments in this period. This data base within the climate information shows us already how the monsoon season behaves in the Haean Valley and in the forest around it. Preliminary results suggested the heavy nitrogen fertilization in the agriculture-dominated Haean basin is the major contributor to the nitrate output into the ground water systems and into the Mandae River and therefore, nitrate input into the Soyang Lake. Nitrate from atmospheric nitrogen deposition or from a surplus of microbial nitrification in the forest-dominated sub-catchments also contributes in smaller amount to nitrate output to the rivers and also suggest differences in nitrate assimilation capacities be-tween the broadleaf and coniferous forest. Keywords: Sub-catchments, fertilizer, nitrate, isotopes signature, atmospheric nitrogen deposition, mi-crobial nitrification, monsoon References • Durka, W; Schulze, ED; Gebauer, G; Voerkelius, S: Effects of forest decline on uptake and leaching of deposited nitrate determined from 15N and 18O measurements, Nature, 372, 765-767 (1994), doi:10.1038/372765a0 • Mayer B, Boyer E.W, Goodale c, Jaworski N.A, Breemen N, Howarth RW, Seitzinger S, Billen G, Lajtha K, Nadelhoffer K, Dam D, Hetling L, Nosal M, Paustian K, 2002 Source of nitrate in rivers drain-ing sixteen watersheds in northeastern US Isotopic constraints. Biogeochemistry 57, 171-197. • Deutsch B, Mewes M, Liskow I, Voss M, Quantification of diffuse nitrate inputs into a small river sys-tem using stable isotopes of oxygen and nitrogen in nitrate; Organic Geochemistry 37 (2006)1333-1342

61

P 20 Tracing stable water isotopes from meteoric to groundwater in the small low-mountainous Schwingbach catchment, Germany

N. Orlowski1,2

, P. Kraft1, H.- G. Frede

1, L. Breuer

1

1Justus-Liebig-University Giessen, Chair of Landscape, Water and Biogeochemical Cycles, Giessen,

Deutschland 2University of Saskatchewan, Global Institute for Water Security, Saskatoon, Kanada

Spatio-temporal sources of stream water in low angle catchments are still poorly understood. This is partly caused by damped stream water isotopic signatures excluding traditional hydrograph separa-tions [1]. Unlike the distinct watershed components found in steeper headwater counterparts (hillslope, hollow), lowland areas often exhibit a complex groundwater-surface water interaction [1]. Conducting a dual stable water isotope (δ

2H and δ

18O) study in the Schwingbach catchment helped to unravel dy-

namics and interactions between precipitation, stream, soil, and groundwater throughout a 2-year ob-servation period.

Precipitation isotopic signatures - ranging from -167.6 to -8.3‰ for δ2H - showed no significant spatial

variance in the study area. However, seasonal variations based on temperature effects were ob-served. Summer precipitation signals differed significantly from stream and groundwater isotopic com-position showing ~20‰ heavier δ

2H values. Damped seasonality of stream water isotopes and almost

uniform δ-values were measured in groundwater, as complex bidirectional interactions between sur-face and groundwater occurred. Apparently, snowmelt played a fundamental role for groundwater re-charge explaining the observed differences to precipitation δ-values.

Comparing the Local Meteoric Water Line (LMWL) of the Schwingbach catchment with the Global MWL showed that the slope is slightly lower due to stronger local evaporation conditions. Moreover, the LMWL of the study area assorts well with the LMWL of the closest GNIP (Global Network of Iso-topes in Precipitation) station Koblenz.

For the soil compartment, enriched δ-values were measured at the soil surface due to evaporation during summer, while the range of isotopic composition decreased with depth. Contrary observations were made in the winter: Depleted isotopic signatures near the soil surface due to snowmelt influence. Evaluating the impact of small-scale factors (topographic wetness index, vegetation cover, distance to stream, and soil physical properties) on soil water isotopic signals revealed that only land use had a significant effect. It appeared that precipitation mixed with existing soil water to some degree and also pushed soil water downwards via piston flow. Thus, the land use influence decreased with depth and soil water approached nearly constant values similar to groundwater isotopic composition.

Tracing stable water isotopes through the water cycle showed that stream water isotopic signatures were in good agreement with groundwater isotopic composition, indicating bidirectional water ex-change. However, the annual isotopic cycle of both streams and groundwater seemed to be decou-pled from the isotopic cycle of precipitation. Thus, groundwater, which was mainly recharged by snowmelt, was the major water contributor to streamflow. Moreover, soil water isotopes were much less variable than that of precipitation and the observed land use impact decreased with depth and approached groundwater δ-values.

Tracing stable water isotopes through the water cycle helped to identify interactions between different water cycle components in a region with little change in individual isotope time series.

References

1. Klaus, J.; McDonnell, J. J.; Jackson, C. R.; Du, E.; Griffiths, N. A. Where does streamwater come from in low relief forested watersheds? A dual isotope approach. Hydrol Earth Syst Sci Discuss 2014, 11, 2613-2638.

62

P 21 Comparison of soil water isotope analysis techniques

B. Gralher1, C. Stumpp

1

1Helmholtz Zentrum München, Institut für Grundwasserökologie, Neuherberg, Deutschland

Environmental tracers like stable isotopes of water (δ18

O, δ2H) have proven to be valuable tools to

study water flow and transport processes in soils. Recently, a new technique for soil water isotope analysis has been developed that employs a vapor phase being in isothermal equilibrium with the liq-uid phase of interest. This has increased the potential application of water stable isotopes in unsatu-rated zone studies as it supersedes laborious extraction of soil water. However, uncertainties of analy-sis and influencing factors need to be considered. Therefore, the objective of this study was to evalu-ate different methodologies of analysing stable isotopes in soil water in order to identify possible pit-falls and assess resulting measurement uncertainty. The methodologies included different preparation procedures of natural soil cores for equilibration of vapor and soil water as well as soil water extrac-tions and additional headspace GC analysis. Two different inflatable sample containers (freezer bags, bags containing a metal layer) and equilibration atmospheres (N2, dry air) were tested. The results showed that uncertainties for δ

18O were higher compared to δ

2H that cannot be attributed to any spe-

cific detail of the processing routine. Particularly, soil samples with high contents of organic matter showed an apparent isotope enrichment which is indicative for fractionation due to evaporation. How-ever, comparison of water samples obtained from cryogenic extraction or suction cups with the local meteoric water line indicated negligible fractionation processes in the investigated soils. We conclude that at least in our case apparent enrichment is an artefact owed to the modality of analysis and show possible correction approaches. We further conclude that the evaluated method is advantageous over traditional methods regarding simplicity, resource requirements and sample throughput but careful consideration needs to be made regarding sample handling and data processing.

63

P 22 Effects of soil properties on the apparent water-vapor isotope equilibrium fractionation: Implications for the headspace equilibration method

B. Herbstritt1, M. Limprecht

1, M. Weiler

1

1Universität Freiburg, Professur für Hydrologie, Freiburg, Deutschland

Stable isotopes of the water molecule (δ18

O, δ2H) have proven to be powerful tools in hydrology with a

long record of applications in precipitation, surface water and groundwater studies. However, there are still significant restrictions when it comes to investigations of the unsaturated zone especially concern-ing soil water extraction for subsequent analysis. The recent invention of laser-based isotope analyz-ers facilitated a workaround and hence a new method for rapid determination of soil water stable iso-tope signatures. This method is based on analyzing the headspace vapor of a sample being in iso-thermal equilibrium with the soil water of interest. However, the employed analyzers are not only sen-sitive to the desired isotopic composition of a given vapor sample but also regarding any gaseous molecule with spectral features similar to those of the water molecule. We suspect that this has a sig-nificant and previously ignored impact on the observed water vapor isotope signature depending on isotope-independent soil characteristics and resulting headspace compositions. We therefore present the results of laboratory experiments which have been performed with five different natural soils and three additional technical substrates. All soils were dried and rewetted with water of known amount and isotopic signature. We also give an estimate of the uncertainty that must be attributed to the headspace equilibration method. Our findings indicate that elevated contents of clay or organic carbon have a systematic impact on apparent isotopic compositions. We propose that future calibration and correction procedures have to take into account these soil characteristics. Especially the co-measured standards used for calibration should be re-evaluated regarding similarity to the samples of interest.

64

P 23 Investigating surface water - groundwater interaction upstream of Hidan well field (Jordan) us-ing stable isotopes

L. Stoeckl1, N. Gassen

2, J. Xanke

3, A. Subah

4, P. Koeniger

1, T. Himmelsbach

1

1Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Deutschland

2Helmholtz Zentrum, München, Deutschland

3Karlsruhe Institut für Technologie, Karlsruhe, Deutschland

4Ministry of Water and Irrigation, Amman, Jordanien

INTRODUCTION: Stable Isotopes of water are an important tool in hydrogeological investigations and can be used to e.g. determine groundwater recharge zones or flow paths. In this study, we used stable isotopes in order to investigate the influence of surface water on groundwater contamination in a semi-arid catchment in central Jordan.

STUDY AREA: The study area is located 18 km southwest of the city of Madaba. Public water supply of Madaba is provided to 100 % by the Hidan well field, which is located at the western (downstream) end of the study area (Figure 1). By this well field, which is located inside the ephemeral wadi Wala, groundwater from a shallow limestone aquifer is extracted. Regular occurring bacterial contamination highly correlates with high surface discharge (flood events) and therefore indicates an exchange be-tween surface water and groundwater. Declining groundwater tables have been stabilized by a re-charge dam, which has been built around 7 km upstream of the well field. Along the wadi course, dry sections alternate with sections of perennial water flow due to several springs and seepage points.

FIGURE 1: a) Map of the study area, b) detailed view of the Hidan well field and c) regional map

OBJECTIVE: In the framework of the Technical Cooperation project “Water Aspects in Land Use Planning”, groundwater protection zones were delineated (Gassen et al., 2014). In this context, the hydrogeological conditions especially in respect to the origin of groundwater contamination were in-vestigated. The objective of the here presented study was to use stable isotope data (deuterium,

2H

and oxygen-18, 18

O) for tracing infiltration water along the wadi, which originates from the reservoir of wadi Wala dam and is therefore enriched in

2H and

18O.

METHODS: Water samples were taken at 21 sites from both ground- and surface waters along wadi Wala over one year and analyzed for d

2H and d

18O. At the same time, rainwater samples were col-

lected in the vicinity of the infiltration dam.

RESULTS: Analyses indicate that the isotopic signature of both surface and groundwater becomes heavier along the wadi course. For the surface water, this effect can be explained by evaporation lead-ing to fractionation. Continued infiltration of surface water along the wadi may also explain the similar evolution of groundwater along the course.

REFERENCES: Gassen, N., Al Hyari, M., Hanbali, B., Obaiat, A., Kirsch, H., Toll, M. & Xanke, J. (2014): Delineation of Groundwater Protection Zones for Hidan Well Field. Fachbericht Nr. 3 des TZ-Projekts 'Wasseraspekte in der Landnutzungsplanung', verfasst von BGR und MWI; 98 S., Amman.

65

Anhang 1

66

P 24 Erforschung von Abflusskomponenten im Tadschikischen Pamir mittels δ

7Li und

87Sr/

86Sr

C. Meier1, K. Osenbrück

2, H.- M. Seitz

3, S. M. Weise

1

1UFZ - Helmholtzzentrum für Umweltforschung GmbH, Catchment Hydrology, Halle (Saale),

Deutschland 2Universität Tübingen , WESS - Water and Earth System Science, Tübingen, Deutschland

3Goethe-Universität, Institut für Geowissenschaften, Frankfurt am Main, Deutschland

Der Aralsee wird von zwei großen Zuflüssen, dem Amudarja und dem Syrdarja, gespeist, die ihre Ur-sprünge im Pamir und Tienshan haben. Im Amudarjaquellgebiet liegt das Einzugsgebiet des Flusses Gunt, welches eine Fläche von ca. 14000 km² umfasst und Höhen zwischen 2000m und 6700m ü. NN aufweist. Die meisten Niederschläge erhält das kalt-aride Gebiet im Winter und Frühling als Regen und Schnee. Dies führt dazu, dass der Abfluss von Schnee- und Gletscherschmelzwasser dominiert wird. Eine große Unbekannte ist der Beitrag von Grundwasser zum Abflussgeschehen.

Um die einzelnen Abflusskomponenten voneinander abtrennen zu können, wurde eine Multi-Isotopenstudie durchgeführt. Dazu wurden entlang des Flusslaufes insgesamt ca. 50 Wasserproben des Hauptstroms, seiner Zuflüsse und an einzelnen Stellen auch Proben von Gletscherschmelz- und Thermalwasser genommen. An den Proben wurden neben den Isotopen des Wassers (D,

18O und

3H)

und den Ionenkonzentrationen auch die stabilen Umweltisotope 7Li und

87Sr untersucht.

Sowohl die Li- als auch die Sr-Isotopensignaturen weisen große Unterschiede in ihrer räumlichen Ver-teilung im Untersuchungsgebiet auf. Die gemessenen Lithium-Isotopenverhältnisse liegen im Bereich der in der Literatur genannten Werte für Flusswasserproben und besitzen eine große Spannbreite zwischen 8‰ und 28‰. Der höchste δ

7Li-Wert wurde an einer Gletscherwasserprobe, der niedrigste

Wert an einer Thermalwasserprobe gemessen. Die Li-Isotopenverhältnisse des Gunt bleiben entlang seiner Fließstrecke von ca. 100km annähernd konstant (δ

7Li=10‰±3‰), wogegen die Zuflüsse unter-

einander große Variationen (δ7LiZuflüsse≥10‰; Δδ

7Li ≈ 12‰) aufweisen. Ebenso divers wie die δ

7Li-

Daten sind die Ergebnisse der 87

Sr/86

Sr-Analysen. Hier reichen die Messwerte der 87

Sr/86

Sr-Verhältnisse von 0,7107 zu 0,7185. Dabei ist mit zunehmender Fließlänge des Flusses Gunt eine Er-höhung der

87Sr/

86Sr-Verhältnisse zu beobachten; auch die Zuflüsse variieren in ihren Sr-

Isotopenverhältnissen (Δ87

Sr/86

Sr ≈ 0,007). In den in dieser Studie untersuchten 87

Sr- und 7Li-

Isotopenverhältnissen spiegeln sich die unterschiedlichen Quellen und Fließstrecken der Flüsse wider.

67

P 25 Towards a Local Meteoric Water Line for Riyadh, Saudi Arabia

N. Michelsen1, M. Reshid

1, C. Siebert

2, S. Schulz

2, R. Rausch

3, M. Al-Saud

4

1TU Darmstadt, Institut für Angewandte Geowissenschaften, Darmstadt, Deutschland

2Helmholtz Zentrum für Umweltforschung, Halle, Deutschland

3Gesellschaft für Internationale Zusammenarbeit International Services, Riad, Saudi Arabien

4Ministry of Water & Electricity, Riad, Saudi Arabien

For arid countries like Saudi Arabia a thorough groundwater resources assessment is crucial and the isotopes

18O and D provide a powerful tool to study the provenance of groundwaters and the

(paleo)climatic conditions during their recharge. Yet, in order to evaluate the isotopic signature of the groundwater, the one of current precipitation has to be known as well. Although a few rain water anal-yses are available for Central Saudi Arabia in the literature - mostly in unpublished consultant reports - a Local Meteoric Water Line has never been established.

In order to complement the available data, 28 rain events occurring in Riyadh between 2009 and 2013 were studied for their stable isotope composition. Samples were collected as integral samples, i.e., they represent the entire precipitation event. Moreover, one event was sampled several times, aiming at an evaluation of intra-storm variability. During selected storms a grab sample was taken for

3H anal-

ysis.

The event samples showed δ18

O and δD values scattering between -6.5 and +9.5 and between -30 and +50 ‰ V-SMOW, respectively. In the course of the event that was sampled several times, an iso-topic depletion was observed with respect to both isotopes. The relatively large ranges of δ values for 18

O and D of approximately 7 and 31 ‰ V-SMOW highlight the general need for integral sampling. The obtained grab samples are characterized by moderate

3H concentrations of a few Tritium Units.

Further results will be presented and discussed in view of associated weather data (e.g. rain amount and temperature) and the probable moisture sources derived from back-trajectories, which were calcu-lated using HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory Model; Draxler & Rolph, 2003).

References

Draxler, R.R. & Rolph, G.D. (2013): HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajecto-ry) Model, access via NOAA ARL READY Website (http://www.arl.noaa.gov/HYSPLIT.php). NOAA Air Resources Laboratory, College Park, MD.

68

Poster

Session 3 – Metabolismus und Physiologie

P 26 Determination of

13C/

12C Ratios of Endogenous Urinary AICAR

T. Piper1, A. Thomas

1, N. Baume

2, T. Sobolevsky

3, M. Saugy

2, G. Rodchenkov

3, W. Schänzer

1,

M. Thevis1

1Deutsche Sporthochschule Köln, Zentrum für präventive Dopingforschung - Institut für Biochemie,

Köln, Deutschland 2Centre Hospitalier Universitaire Vaudois and Université Lausanne, Swiss Laboratory for Doping

Analysis, Lausanne, Schweiz 3Antidoping Centre Moscow, Moscow, Russland

Rationale: AICAR (5-Aminoimidazole-4-carboxamide 1β-D-ribofuranoside) is prohibited in sport ac-cording to rules established by the World Anti-Doping Agency. Doping control laboratories identify samples suspicious of AICAR abuse by measuring its urinary concentration and comparing the ob-served level to naturally occurring concentrations. As the inter-individual variance of urinary AICAR concentrations is large, this approach requires a complementary method to unambiguously prove the exogenous origin of AICAR. Therefore a method for the determination of carbon isotope ratios (CIR) of urinary AICAR has been developed and validated.

Methods:Concentrated urine samples were fractionated by means of liquid chromatography for analyte clean up. Derivatization of AICAR yielding the trimethylsilylated analog was necessary to enable CIR determinations by gas chromatography-combustion-isotope ratio mass spectrometry. The method was tested for its repeatability and stability over time and a linear mixing model was applied to test for pos-sible isotopic discrimination. A reference population of n = 63 males and females was investigated to calculate appropriate reference limits to differentiate endogenous from exogenous urinary AICAR. These limits were tested by an AICAR elimination study.

Results:The developed method fulfills all requirements for adequate sports drug testing and was found to be fit for purpose. The investigated reference population showed a larger variability in CIR of AICAR as for endogenous steroids. Nevertheless, the calculated thresholds for differences between AICAR and endogenous steroids can be applied straightforward to evaluate suspicious doping control sam-ples with the same statistical confidence as established e.g. for testosterone misuse. These thresholds enabled the detection of a single oral AICAR administration for more than 40 h.

Conclusion:Determination of CIR is the method of choice to distinguish between an endogenous or exogenous source of urinary AICAR. The developed method will enable investigations into doping control samples with elevated urinary concentrations of AICAR and clearly differentiate between natu-rally produced/elevated and illicitly administered AICAR.

69

P 27 Nitrogen Isotope Ratios of Endogenous Urinary AICAR

T. Piper1, A. Thomas

1, W. Schänzer

1, M. Thevis

1

1Deutsche Sporthochschule Köln, Zentrum für präventive Dopingforschung - Institut für Biochemie,

Köln, Deutschland

AICAR (5-Aminoimidazole-4-carboxamide 1β-D-ribofuranoside) is prohibited in sport according to rules established by the World Anti-Doping Agency. Doping control laboratories identify samples sus-picious of AICAR abuse by measuring its urinary concentration and comparing the observed level to naturally occurring concentrations. As the inter-individual variance of urinary AICAR concentrations is large, this approach requires a complementary method to unambiguously prove the exogenous origin of AICAR. In parallel to carbon isotope ratios the

15N/

14N ratio of AICAR should allow for allocation of

urinary AICAR regarding its endogenous or exogenous source.

The nitrogen atoms in AICAR (being part of the purine biosynthesis pathway) derive from glutamine, glycine and aspartatic acid. In parallel to amino acids investigated in hair, plasma or bone tissue it is expected that endogenous nitrogen isotope ratios show enriched values of up to +15 ‰ (δ

15NAIR).

Sample preparation was done accordingly to the method employed for carbon isotope ratios. As ex-pected, limits of detection were found approx. 5 times higher than for carbon measurements resulting in a minimum required urinary concentration of 1000 ng/mL AICAR for a 3 mL aliquot. Within this pre-liminary investigation 4 blank urines containing only endogenous AICAR (as ensured by

13C/

12C

measurements), 1 post administration sample collected after oral ingestion of 10 g of AICAR and a reference standard were determined. The standard was also investigated by means of elemental ana-lyzer/isotope ratio mass spectrometry to test for bias introduced by gas chromatographic separation and online conversion of samples prior to isotope ratio measurements. Reference material IAEA 600 was used to calibrate nitrogen tank gas.

Within these first measurements no significant difference was found between the nitrogen isotope rati-os of endogenous AICAR, the post-administration value and the standard material. Further AICAR standards and seized black market products should be analyzed to verify a similar homogenous iso-topic signature for nitrogen as was found for carbon isotope ratios so far.

70

P 28 The metabolic effect of pre- and probiotics on the renal and faecal nitrogen and ammonia ex-cretion in humans as measured by lactose-[

15N2]ureide degradation

K.- D. Wutzke1, D. Scholübbers

1, M. Wigger

1

1Universitäts-Kinderklinik Rostock, Forschungslabor, Rostock, Deutschland

Introduction: It can be considered as certain that both pre- and probiotics in the form of resistant starch (RS) and yoghurt, respectively, have a significant impact on the colonic ammonia metabolism in humans. It is assumed that the metabolic interplay of RS and yoghurt when supplemented simultane-ously contributes to an increased saccharolytic activity and to a corresponding decreased proteolytic activity of the colonic microbiota which is beneficial for the host. This may cause an enhanced detoxif i-cation effect by discharging ammonia via the faeces resulting in a corresponding reduced excretion in urine, particularly in urinary ammonia. The evaluation of ammonia detoxification by pre- and probiotics, respectively, by means of bacterial lactose-[

15N2]ureide (

15N-LU) degradation to

15NH3 and its excretion

is still of great interest, scientifically in terms of nutrition physiology, and commercially. In the present study, RS and Lactobacillus acidophilus yoghurt (LC1) were supplemented simultaneously to evaluate the effect on the urinary and faecal nitrogen and ammonia excretion by means of

15N-LU degradation.

Material and Methods: A total of 19 healthy adults (14 female, 5 male) aged 20-32 years received a regular daily diet either without (no treatment, NT) or with supplementation of a RS-LC1-mixture (MIX) composed of 15 g fibre of potatoes (RS type 1), 15 g wrinkle pea starch (RS type 2, Emsland Group, Emlichheim, Germany), and 190 g LC1 (Nestlé AG, Frankfurt/Main, Germany) over a 20-day period in randomized order. Thereafter, 5.7 mg/kg body weight

15N-LU was administered together with break-

fast. Urine and faeces were collected over a period of 48 and 72 h, respectively. Urinary ammonia was separated in micro-diffusion vessels followed by alkalization and trapped in boric acid. The

15N-

abundances were measured by isotope ratio mass spectrometry (TracerMass 20-20, SerCon, Crewe, UK).

Results: The mean renal 15

N-excretion differed significantly (t-test) between the supplementation of the MIX and NT (34.9 vs. 43.8%, p=0.015). The mean faecal

15N-excretion amounted to 43.6% (MIX)

and 34.1% (NT). In comparison with NT (0.1%) the urinary 15

NH3-excretion was significantly de-creased after the MIX supplementation (0.05%, p=0.001).

Conclusions: The urinary 15

N-excretion between 0-6 h mainly reflects the glucose-[15

N2]ureide ab-sorption deriving from the enzymatic degradation of

15N-LU by β-galactosidase in the small bowel. The

intake of a pre- and probiotic mixture composed of RS1+RS2+LC1 significantly lowered the colonic generation and the renal excretion of toxic

15NH3 and functioned as an ammonia shift from urinary to

faecal 15

N-excretion when using 15

N-LU as a xenobiotic marker. When summarising our findings, we are convinced that

15N-LU is a valid tool for investigating nitrogen and ammonia metabolism in the co-

lon. The measurement the urinary 15

NH3-excretion using 15

N-LU is a novelty.

References: Wutzke KD, Lotz M, Zipprich C: The effect of pre- and probiotics on the colonic ammonia metabolism in humans as measured by lactose-[

15N2]ureide. Eur J Clin Nutr 2010;64:1215-21.

71

P 29 Surprising effect of experimental bacterial infection of grass carp on δ

13C in fish in spite of on-

ly minimal intense clinical symptoms

R. Mayrhofer1, J. Pucher

2, M. El-Matbouli

1, U. Focken

3

1Veterinärmedizinische Universität Wien, Wien, Österreich

2Universität Hohenheim, Life Science Center, Stuttgart, Deutschland

3Thünen-Institut für Fischereiökologie, Ahrensburg, Deutschland

The macro-herbivorous grass carp is one of the most produced fish species worldwide. In Asia, there are regional mass mortalities of grass carp which occur seasonally. The mass mortalities might be caused by a multi-factorial disease triggered by environmental factors, malnutrition, pesticides and bacterial infection with Aeromonas hydrophila (Pucher et al. 2013). Asian farmers use banana leaves to prevent disease outbreaks without any scientific proof yet. In this study, banana leaves were used as feed for grass carp to investigate its phyto-prophylactic effect to prevent clinical signs through the infection with Aeromonas hydrophila. Further, the effect of the bacterial infection and feeding on the isotopic signature in grass carp was tested.

In a 42 weeks feeding and infection trial, 6 groups of 10 grass carp (15-20 cm body length) were fed by one of three different feeds managements. All fish were fed by full pellet feed (Garant-Tiernahrung GmbH) at 7 g kg

-0.8. Six groups were additionally fed fresh banana leaves and six other by fresh maize

leaves (Table 1). After 10 month, three groups of each feeding treatment were challenged by Aeromonas hydrophila. Growth performance and clinical signs were observed. After 10 days, fish were analysed for chemical composition. In extracted lipid and lipid-free fish and feeds, isotopic signatures of carbon were determined by Elemental Analyzer (Euro Vector) and a Thermo Finnigan Delta Plus IR-MS.

Fish growth was similar regardless feeds and infection. Intramuscular infection of fish resulted in skin irritations; 14 fish died. Any phyto-prophylactic effects were identified. Fish fed only pellet feed had a significant higher lipid content.

TABLE 1

The different leaves as feed changed significantly the carbon isotopic signature in the lipid and lipid-free fraction. Infection significantly changed carbon isotopic signature in lipids regardless the feeds.

As a conclusion, no phyto-prophylactic effect of banana leave as feed for grass carp was detected. Carbon isotopic signature of the lipid fraction might be worth to look at as a potential indicator for bac-terial infections.

Reference

Pucher J, Steinbronn S, Mayrhofer R, Schad I, El-Matbouli M, Focken U (2013) Improved Sustainable Aquaculture Systems for Small-Scale Farmers in Northern Vietnam. In: Fröhlich et al. (eds.) Sustaina-ble Land Use and Rural Development in Southeast Asia: Innovations and Policies for Mountainous Areas. Springer Verlag, Berlin, pp. 281-317

Table 1: Isotopic composition of the lipid and lipid-free fraction of feeds and of fish under the three feeding managements and infection.

Anhang 1

72

P 30 „Hydraulic redistribution“ über Wurzeln von Buche, Eiche und Fichte - Ergebnisse eines „Split-root“-Experiments

B. Hafner1, M. Tomasella

1, K.- H. Häberle

1, R. Matyssek

1, T. E. E. Grams

1

1Technische Universität München, Lehrstuhl für Ökophysiologie der Pflanzen, Freising/

Weihenstephan, Deutschland

„Hydraulic Redistribution“ bezeichnet die Umverteilung von Wasser im Boden durch die Wurzeln einer Pflanze. Diese Umverteilung richtet sich entlang eines Wasserpotenzialgradienten. Sie kann sowohl vertikal als auch horizontal erfolgen. In dem hier vorgestellten „Split-root“-Experiment wird das Poten-tial zur hydraulischen Umverteilung verschiedener Baumarten untersucht.

Junge Buchen, Eichen und Fichten (2 Jahre alt, 30-60 cm groß) wurden in „Split-root“-Töpfe gepflanzt, d.h. je drei Bäume wurden auf je zwei Pflanztöpfe so aufgeteilt, dass sich pro Topf eine Pflanze be-fand und die dritte so gepflanzt wurde, dass ihre Wurzeln in beiden Töpfen wachsen konnten (Abb. 1). Ein Kontakt zwischen den beiden Töpfen bestand anschließend ausschließlich durch die Wurzeln der mittleren Pflanze („split-root plant“). Gepflanzt wurden jeweils 3 Buchen, Fichten oder Eichen und ver-schiedene Kombinationen dieser 3 Arten. Je Kombination wurden 7 Wiederholungen angelegt. Nach-dem die Pflanzen 4 Monate anwachsen konnten, wurde ein Feuchtigkeitsgradient zwischen den Töp-fen eingestellt. Die Pflanze in Topf 2 wurde trockengestresst wofür der Wassergehalt auf ca. 15 vol.% reduziert wurde, während die Pflanze in Topf 1 weiterhin gut bewässert wurde (Wassergehalt 30-40 vol.%). Nachdem der Gradient über mehrere Tage stabil war (regelmäßige Überprüfung mit einer TDR Sonde), wurde die gut bewässerte Pflanze (Topf 1) mit 300 mL Deuterium-gelabeltem Wasser gegos-sen (δD: ca. 6.000 ‰). Nach 1 und 3 Tagen wurden Proben von Boden, Xylem und Wurzel aus dem gelabelten und ungelabelten Topf sowie der „split-root“-Pflanze genommen, um eine mögliche hori-zontale Umverteilung des Wassers über die „split-root“-Pflanze nachzuweisen. Sollte gelabeltes Was-ser im Boden, der Wurzel oder dem Xylem der ungelabelten Seite vorhanden sein, wäre „Hydraulic Redistribution“ nachgewiesen. Hierfür wurde per Cryo-Destillation das Wasser aus den Proben extra-hiert und dieses schließlich mit einem Isotopenverhältnis-Massenspektrometer (IRMS, Isotope-Ratio-Mass-Spectrometry) auf den Deuteriumgehalt analysiert.

Die Hypothesen lauten, dass (1) alle drei Baumarten (Buchen, Eichen und Fichten) in der Lage sind, entlang einem Feuchtigkeitsgradienten Wasser umzuverteilen, (2) dass dieses Wasser anderen Pflan-zen zur Verfügung steht und (3) die Menge des umverteilten Wassers proportional zu dem bestehen-den Feuchtigkeitsgradienten ist.

Anhang 1

73

P 31 13

C/12

C ratios of 5α-androst-1-ene-3,17-dione in human urine

P. Riemann1, G. Fußhöller

1, N. Haenelt

1, V. Gougoulidis

1, A. Macha

1, D. Müller

2, U. Flenker

1,

M. K. Parr3, W. Schänzer

1

1Deutsche Sporthochschule Köln, Institut für Biochemie, Köln, Deutschland

2Deutsche Sporthochschule Köln, Institut für Kreislauffoschung und Sportmedizin, Köln, Deutschland

3Freie Universität Berlin, Institut für Pharmazie, Berlin, Deutschland

5α-Androst-1-ene-3,17-dione (1-AD) is an anabolic-androgenic steroid listed on the World Anti-Doping Agency’s prohibited list under section S1.a (exogenous anabolic androgenic steroids). Within the years 2004 to 2014 several routine doping control samples were tested positive for this steroid.

In the last two years several urine specimens, obtained during routine doping control showed evidence of bacterial activity combined with trace amounts of 1-AD in the range of 7-40ng/mL.

If in only low concentrations, several studies showed that 17β-hydroxyandrosta-1,4-dien-3-one (Boldenone, Bo) of potentially endogenous origin can be detected in human urine. A probable reason for the formation of Bo in humans can be found in bacterial enzymes with Δ

1-dehydrogenase activity.

Corresponding bacteria (e.g. Clostridium paraputrificum, Escherichia coli) are known to exist in human intestine or in urine.

The existence of an analogues pathway to 1-AD appears reasonable

Although, samples with bacterial activity are reported as invalid to the doping control authorities the investigation of the origin of 1-AD in this urines appears reasonable. Fundamentally, GC-C-IRMS analysis is the method of choice to discriminate between endogenous or synthetic origin of these compounds.

In order to investigate the source of 1-AD a method for 13

C/12

C analysis of urinary 1-AD has been de-veloped. This includes several (HPLC) purification steps.

13C/

12C ratios of 1-AD and other selected en-

dogenous steroids were determined.

Additionally 13

C/12

C data from an excretion study with 1-AD were analyzed to demonstrate the general possibility to distinguish between an endogenous or synthetic origin of 1-AD. These data fundamental-ly demonstrate the synthetic origin of 1-AD. After application a strong enrichment in

13C of 1-AD over

the time of sample collection was observed.

By contrast, the analysis of the routine doping control samples with bacterial activity yielded in incon-sistent results.

74

P 32 Distribution of recently assimilated carbohydrates from

13CO2 between different species of

ectomycorrhizal fungi under water stress conditions

U. Geppert1, R. Kerner

1, J.- C. Munch

1, M. Arend

2, K. Pritsch

1

1Helmholtz Zentrum München, Institut für Bodenökologie, Neuherberg, Deutschland

2Eidgenössische Forschungsanstalt für Walds, Schnee und Landschaft, Walddynamik, Birmensdorf,

Schweiz

To better predict reactions of vegetation on future climate changes our knowledge on water stress has to be improved considerably (Xu et al., 2013). It has been shown that mycorrhizal plants have an im-proved water status compared to non mycorrhizal controls (Lehto & Zwiazek, 2011). Different mycorrhizal fungi are ecologically beneficial to the plant in very varying ways (Agerer, 2001; Pritsch et al., 2004). To gain more insight into the regulation (i.e. carbon supply) of the mycorrhiza by the plant (Kiers et al., 2011) under water stress conditions we want to analyse the distribution of recently assimi-lated carbohydrates from

13CO2 between different species of ectomycorrhizal fungi. With analyses of

δ13

C of the root tips in a time course we are able to follow the temporal distribution of the assimilates within the plant (Högberg et al., 2008). By using two complementary methods (RNA-SIP and NanoSIMS) we want to identify the most active fungal partners of the plant before and after rewatering and in addition study the spatial distribution of labelled carbohydrates within the mycorrhizal root tip. First preliminary results from the experiment “BuKlim” at the WSL in Switzerland will be presented.

Agerer, R. (2001) Exploration types of ectomycorrhizae - A proposal to classify ectomycorrhizal mycelial systems according to their patterns of differentiation and putative ecological importance. Mycorrhiza, 11, 107-114.

Högberg, P., Högberg, M., Göttlicher, S., Betson, N., Keel, S., Metcalfe, D., Campbell, C., Schindlbacher, A., Hurry, V. & Lundmark, T. (2008) High temporal resolution tracing of photosynthate carbon from the tree canopy to forest soil microorganisms. New Phytologist, 177, 220-228.

Kiers, E.T., Duhamel, M., Beesetty, Y., Mensah, J.A., Franken, O., Verbruggen, E., Fellbaum, C.R., Kowalchuk, G.A., Hart, M.M., Bago, A., Palmer, T.M., West, S.A., Vandenkoornhuyse, P., Jansa, J. & Bucking, H. (2011) Reciprocal Rewards Stabilize Cooperation in the Mycorrhizal Symbiosis. Science, 333, 880-882.

Lehto, T. & Zwiazek, J.J. (2011) Ectomycorrhizas and water relations of trees: a review. Mycorrhiza, 21, 71-90.

Pritsch, K., Raidl, S., Marksteiner, E., Blaschke, H., Agerer, R., Schloter, M. & Hartmann, A. (2004) A rapid and highly sensitive method for measuring enzyme activities in single mycorrhizal tips using 4-methylumbelliferone-labelled fluorogenic substrates in a microplate system. Journal of Microbiological Methods, 58, 233-241.

Xu, C., McDowell, N.G., Sevanto, S. & Fisher, R.A. (2013) Our limited ability to predict vegetation dy-namics under water stress. New Phytologist, 200, 298-300.

75

P 33 Transamination governs the heterogeneity in nitrogen isotope composition of amino acids in the muscle

A. Braun1, A. Vikari

1, W. Windisch

1, K. Auerswald

1

1Technische Universität München, Freising, Deutschland

The nitrogen isotope composition (δ15N) of different amino acids carries different dietary information. We hypothesized that differences in their biochemical pathways create three groups that largely ex-plain their dietary information. The groups divide into (i) transaminating, (ii) non-transaminating and essential and (iii) non-transaminating and non-essential amino acids.

To this end, rats were fed with 15N-labeled amino acids, where each amino acid had an individual ni-trogen isotope composition that varied by ~1000‰ among amino acids. The redistribution of the die-tary 15N labels among the amino acids in the muscle of the rat was analyzed. Subsequently, the label-ing was changed and the nitrogen isotope turnover was analyzed.

The amino acids had a common nitrogen half-life of ∼20 d, but differed in δ15N. Nontransaminating and essential amino acids largely conserved the δ15N of the diet and, hence, trace the origin in heter-ogeneous diets. Nonessential and nontransaminating amino acids showed a nitrogen isotope compo-sition between their dietary composition and that of their de novo synthesis pool, likely indicating their fraction of de novo synthesis. The bulk of amino acids, which are transaminating, derived their N from a common N pool and hence their δ15N in the muscle was similar, although it varied by two orders of magnitude in the diet.

The original article was published in the Journal of Agricultural and Food Chemistry (see dx.doi.org/10.1021/jf502295f).

76

P 34 Carbon allocation to new leaves increases carbon isotope differences between plant organs

F. Wegener1, C. Werner

1

1Uni Bayreuth, Agrarökosystemforschung, Bayreuth, Deutschland

Plant organs of C3 plants differ in their carbon (C) isotopic signature (δ13

C). In general, leaves are 13

C-depleted relative to other organs. To investigate the development of spatial δ

13C-patterns, we induced

different C-allocation strategies by reducing light and nutrient availability for twelve months in the Mediterranean shrub Halimium halimifolium L. We measured morphological and physiological traits and the spatial δ

13C-variation between up to seven tissue classes during the experiment. A reduction

of light (Low L treatment) increased aboveground C-allocation, plant height and specific leaf area (SLA). Reduced nutrient availability (Low N treatment) enhanced C-allocation into fine roots and re-duced the spatial δ

13C-variation. In contrast, control and Low L plants with high C allocation in new

leaves showed a high δ13

C-variation within the plant (up to 2.5‰). The spatial δ13

C-variation was sig-nificantly correlated to the percentage of the second generation leaves from the whole plant biomass (R

2=0.46). According to our results fractionation in dark respiration may influence C-isotope composi-

tion of the plant tissues but it cannot explain the spatial pattern. Our study indicates that the main rea-son for the observed spatial δ

13C-pattern in H. halimifolium is a foliar depletion in

13C during leaf de-

velopment combined with export of relatively 13

C enriched C by mature source leaves.

77

P 35 Nachweis präferenzieller Aufnahme von

15N-,

18O- und

2H- Tracer in unterschiedlichen

Pflanzenorganen von Weizen und Bohnen

K. Werner1, B. Glaser

1, M. Zech

2,1

1Martin-Luther-Universität Halle-Wittenberg, Bodenbiogeochemie, Halle, Deutschland

2Universität Bayreuth, Lehrstuhl für Geomorphologie, Bayreuth, Deutschland

Stabilisotopenanalysen sind zu einem wertvollen Werkzeug in vielen unterschiedlichen wissenschaftli-chen Bereichen geworden. Auch bei der Untersuchung von Stoffkreisläufen und pflanzenphysiologi-schen Fragestellungen können entsprechende Ergebnisse wertvolle Erkenntnisse liefern.

Im Rahmen der hier vorgestellten Studie wurden wenige Tage alte Weizen- und Bohnenpflanzen mit 15

N (KNO3), 2H- und

18O (H2O)-Tracer gelabelt um zu untersuchen ob der Einbau der Tracer in unter-

schiedlichen Pflanzenorganen präferenziell erfolgt. Zwei Tage nach Applikation der Tracer erfolgte die Beprobung. Bei den Bohnen wurden die Wurzeln, der Halm sowie der äussere- und innere Teil des ersten Blattes beprobt; beim Weizen wurden die Wurzeln, der untere und obere Teil des Keimblattes sowie der untere, mittlere und obere Teil des Sprosses beprobt.

Die Ergebnisse zeigen, dass bei den Bohnen die Traceraufnahme in unterschiedliche Pflanzenorgane abhängig vom verwendeten Tracer variieren kann. Beim Weizen zeigt sich dagegen eine stark präfe-renzielle Aufnahme aller Tracer im unteren Teil des Keimblattes wie auch dem unteren Teil des Sprosses. Erklären lässt sich dieses Ergebniss mit den interkalaren Wachstumsmeristemen von Grä-sern und der dort stattfindenden hohen Biomasseproduktion.

Von Bedeutung ist dieser Befund u.a. für paläoklimatische Studien die δ2H von Alkanbiomarkern oder

δ18

O von Zuckerbiomarkern untersuchen. Die Ergebnisse verdeutlichen nämlich, dass diese Biomar-ker in Gräsern nicht primär an den Blattspitzen produziert werden wo starke Isotopenanreicherung durch Verdunstung stattgefunden hat, sondern primär im Bereich der interkalaren Wachstumsmeris-teme wo noch keine signifikante Verdunstung stattgefunden hat.

78

P 36 Isotopic alterations during phloem translocation in two forest tree species

R. Bögelein1, W. Werner

1, F. M. Thomas

1

1Geobotany, Faculty of Regional and Environmental Sciences, University of Trier, Trier, Deutschland

The carbon and oxygen isotopic signatures of assimilated carbohydrates keep record of the ecophysiological conditions under which they were formed. Extracts of water-soluble organic matter from leaves have been shown to represent the fast turnover fraction and can be related to water-use efficiency, stomatal conductance and the rate of photosynthesis of the preceding hours or days. How-ever, in the process of phloem loading and transport to the stem, the signals may be altered. There-fore, the quality of ecophysiological information that is retained during the travel to the stem phloem is under current debate. Knowledge of these relationships is also a prerequisite for the use of tree ring cellulose for ecological studies.

In our study, we followed the isotopic signals of water-soluble organic matter from the foliage of three different canopy heights across twig and branch phloem down to the stem phloem. The sampling was repeated seasonally in European beech and Douglas-fir growing in pure and mixed stands.

In the water-soluble organic matter, the oxygen isotope enrichment was strongly dampened from the leaf to the twig phloem. The dampening was most pronounced in the shaded crown layers of species. In the upper crown regions, phloem organic matter kept most of the leaf signal in mid and late sum-mer. In comparison, the further alterations of the oxygen isotopic signatures on the way down to the stem phloem were inferior. However, while the depletion of

18O with decreasing height was mostly

continuous in Douglas-fir, the lowest D18

O values (28.9 ± 1.5‰) in beech were found at the crown base rather than at breast height.

Our results give evidence, that, in the two investigated species, the oxygen isotopic signature of stem phloem organic matter is partly uncoupled from the leaf level.

Keywords: d18

O, d13

C, Fagus sylvatica, Pseudotsuga menziesii

79

Poster

Session 4 – Geochemische Stoffkreisläufe und Schadstoffdynamik

P 37 Methodenvergleich zur Bestimmung der Denitrifikation im Freiland -

15N Tracertechnik vs.

Isotopomere

C. Buchen1, H. Flessa

1, A. Giesemann

1, D. Lewicka-Szczebak

1, R. Well

1

1Thünen-Institut für Agrarklimaschutz, Braunschweig, Deutschland

Denitrifikation, die Reduktion von Nitrat (NO3-) und Nitrit (NO2

-) zu Stickoxiden (NOx), Lachgas (N2O)

und molekularem Stickstoff (N2) gilt als Senkenprozess für reaktiven Stickstoff in Ökosystemen. Sie stellt eine zentrale Bilanzgröße für die Verfügbarkeit von mineralischem Stickstoff für die Verminde-rung von NO3

- Einträgen in Grund- und Oberflächengewässer, sowie Emissionen des klimarelevanten

Treibhausgases N2O in landwirtschaftlich genutzten Systemen dar.

Die Teilreaktionen der Denitrifikation sind jedoch nicht leicht zu bestimmen und eine große Unsicher-heit ergibt sich bei der Abschätzung der N2O Reduktion zu N2, welche besonders im Freiland äußerst schwierig zu messen ist. Zur Quantifizierung dieser Prozesse werden in einem Freilandversuch zu Grünlanderneuerung und -umbruch erstmals zwei unterschiedliche Methoden (Isotopomer-Ansatz und die

15N2-Methode) verglichen:

Im Isotopomer-Ansatz werden unter Anwendung eines Isotopenfraktionierungsmodells (Lewicka-Szczebak, Well et al. 2014) wöchentlich die δ

18O, δ

15N und die

15N Positionspräferenz (SP) von N2O in

Gasproben aus geschlossenen Kammern auf Parzellenebene bestimmt. Gleichzeitig erfolgt die Be-stimmung von δ

15N und δ

18O im NO3

- und δ

18O im Bodenwasser, als Vorläuferverbindung von N2O

aus der Denitrifikation.

Zur Anwendung der 15

N2-Methode erfolgte eine 15

N-Markierung des Nitratpools in Mikroplots. Über ei-ne Versuchsdauer von 8 Wochen wurden NO3

--Konzentration und

15N-Anreicherung in der Bodenlö-

sung sowie die N2 und N2O Emissionen in Gasproben aus geschlossenen Kammern und Bodenson-den bestimmt.

Erste Ergebnisse des Isotopomer-Ansatzes weisen auf hohe Denitrifikationsraten sowie eine weitge-hende N2O-Reduktion zu N2 hin, welches durch die großen N2 Emissionen nach

15N Markierung sowie

ein geringes N2O/(N2+N2O)-Verhältnis bestätigt werden kann. Weitere Ergebnisse des Methodenver-gleichs werden folgen.

Literatur:

Lewicka-Szczebak, D., R. Well, J. R. Köster, R. Fuß, M. Senbayram, K. Dittert and H. Flessa (2014). "Experimental determinations of isotopic fractionation factors associated with N2O production and re-duction during denitrification in soils." Geochimica et Cosmochimica Acta 134: 55-73.

80

P 38 Enzymatische Hydrolyse von Atrazin:

15N/

14N Isotopeneffekte liefern Hinweise für N-

Protonierung in Amidohydrolase TrzN und dessen Mutant TrzN-E241Q

H. K. V. Bensch1, J. L. Seffernick

2, A. Grzybkowska

3, A. Dybala-Defratyka

3, L. P. Wackett

2, M. Elsner

1

1Helmholtz Zentrum München, Institut für Grundwasserökologie, Neuherberg, Deutschland

2University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics, Minnesota,

Vereinigte Staaten von Amerika 3Lodz University of Technology, Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz,

Polen

Fragestellung

Der biologische Abbau von Atrazin ist von großem Interesse, da es sich bei diesem Herbizid um einen potentiellen Grundwasserschadstoff handelt. Einen der wichtigsten Abbauwege stellt die mikrobiologi-sche Umwandlung von Atrazin zu 2-Hydroxyatrazin dar, die durch das Enzym TrzN katalysiert wird. Die Kristallstruktur von TrzN wurde von Seffernick et al. (2010) aufgeklärt und lässt vermuten, dass sich Glutaminsäure E241 in unmittelbarer Nähe zu einem Stickstoffatom des Substratringes befindet und dort durch Protonierung den Katalysezyklus startet. Der Protonierung folgt dann eine nucleophile aromatische Substitution (SNAr) der C-Cl Bindung. Experimente mit dem Bakterienstamm Arthrobacter aurescens TC1, der das Enzym TrzN exprimiert (Meyer et al., 2009), zeigten eine inverse Stickstoff-isotopenfraktionierung und stützen damit den von Seffernick et al. (2010), vorgeschlagenen Katalysezyklus (N-Protonierung, gefolgt von SNAr). Ähnliche Experimente auf Enzymebene fehlten je-doch bisher. Im Mutanten TrzN-E241Q wurde im reaktiven Zentrum, durch eine zielgerichtete Mutagenese von TrzN, Glutaminsäure E241 durch Glutamin Q241 ersetzt. Dieser Mutant zeigte im Vergleich zum nativen Enzym TrzN einen langsameren Substratumsatz (Seffernick et al., 2010). Dies wirft die Frage auf, ob die Fähigkeit zur Protonierung - und somit zum Abbau von Atrazin - im mutier-ten Enzym weiter besteht oder das Substrat auf andere Weise zu 2-Hydroxyatrazin umgewandelt wird. Zu diesem Zweck wurden in der vorliegenden Studie die substanzspezifischen Kohlenstoff- und Stick-stoffisotopeneffekte bei der Reaktion von Atrazin mit TrzN und bei der Reaktion von Atrazin mit TrzN-E241Q bestimmt. Dabei werden inverse Stickstoffisotopeneffekte erwartet, wenn Stickstoffatome protoniert werden, andernfalls werden normale Isotopeneffekte erwartet. Für Kohlenstoff werden in beiden Fällen normale Isotopeneffekte erwartet.

Ergebnisse und Schlussfolgerungen

Die Messung der Isotopeneffekte mittels GC-IRMS (Gaschromatographie-Isotopenverhältnismassenspektrometrie) ergab für beide Reaktionen normale Kohlenstoff-isotopeneffekte. Der Stickstoffisotopeneffekt war überraschenderweise in beiden Fällen invers. Dies deutet darauf hin, dass das mutierte Enzym TrzN-E241Q trotz Verlustes der Säurefunktion weiterhin das Substrat protoniert. Eine mögliche Erklärung für diese Ergebnisse lieferte eine erneute Analyse der Kristallstrukturen von TrzN und TrzN-E241Q, bei der zwei Wassermoleküle eine wichtige Rolle spielen. Eines dieser Wassermoleküle überträgt sein Proton über Histidin H274 an E241. Das verblei-bende Hydroxidion dient im weiteren Verlauf der Reaktion als Nucleophil. Das zweite Wassermolekül befindet sich mit einem Abstand von 2.83 Å in unmittelbarer Nähe des Substratringes und könnte im Falle des mutierten Enzyms TrzN-E241Q die Protonierung des Substrates übernehmen. Diese Über-legungen werden durch quantenmechanische Berechnungen gestützt.

Seffernick, J.L., Reynolds, E., Federov, A.A., Almo, S.C., Sadowsky, M.J., Wackett, L.P. X-ray Structu-re and Mutational Analysis of the Atrazine Chlorohydrolase TrzN. J. Biol. Chem. 2010, 285, 30606-30614.

Meyer, A.H., Penning, H., Elsner, M. C and N Isotope Fractionation Suggests Similar Mechanisms of Microbial Atrazine Transformation Despite Involvement of Different Enzymes (AtzA and TrzN). Envi-ron. Sci. Technol. 2009, 43, 8079-8085.

81

P 39 Tracking photochemical transformation of chloroanilines using compound-specific isotope analysis

M. Ratti1,2

, S. Canonica1, K. McNeill

2, T. Hofstetter

1,2

1EAWAG, Environmental Chemistry, Dübendorf (ZH), Schweiz

2ETH, Institute of Biogeochemistry and Pollutant Dynamic, Zürich (CH), Schweiz

Due to their use as industrial chemicals, biocides, and pharmaceuticals, substituted anilines are fre-quently found in the environment. Identifying the transformation pathways of substituted anilines is challenging because these compounds can undergo both biological and abiotic oxidation as well as photochemical reactions with excited triplet states of natural organic matter and direct photolysis. To identify and distinguish these pathways without the need for finding reaction products, we explore the use of compound-specific isotope analysis. This approach is based on the combined interpretation of changing C and N isotope composition of substituted anilines due to kinetic and equilibrium isotope effects as indicators for transformation. While some information the isotope effects associated with mi-crobial and abiotic oxidation already exists, none is available for photochemical reactions. In the pre-sent study, we explore the apparent

13C- and

15N-kinetik isotope effects (AKIEs) associated with the

direct photolysis of chlorinated anilines. Our results have shown that chlorinated anilines exhibit a very variable isotope fractionation associated with different mechanisms of photochemical dechlorination reactions. The isotope effects are sensitive to substrate speciation in the pH-range 2.0 to 9.0 and the position of the aromatic Cl substituent.

13C- and

15N-AKIE-values for 4-Cl-aniline range from 1.005 to

1.017 and 1.001 to 1.008, respectively. Smaller 13

C- and 15

N-AKIEs that were almost identical in mag-nitude were observed for 3-Cl-aniline photolysis (0.997 at pH 2.0 to 1.002 at pH 7.0). Finally,

13C-

AKIEs for 2-Cl-aniline photolysis were inverse (0.990 at pH 4.0 and 0.992 at pH 7.0), while 15

N-AKIEs were normal (1.003 at pH 4.0 and 7.0). Using singlet quencher, we found that the pH-dependent iso-tope fractionation of 4-Cl-aniline is likely due to reactions from singlet vs. triplet excited states. Similar trends were also observed for 2-Cl- and 3-Cl-aniline. The large variation in both

13C- and

15N-AKIE-

values suggests that direct photolysis is associated with mass-independent isotope fractionation, which is distinctly different from that found in biotic and abiotic oxidation reactions.

82

P 40 DDT’s isotopic signature: Tracing pollutant turnover by NMR

I. Ehlers1, T. Betson

1, W. Vetter

2, J. Schleucher

1

1Umeå University, Umeå, Schweden

2Universität Hohenheim, Stuttgart, Deutschland

Persistent organic pollutants (POPs) have severe toxic effects on the environment and pose risks to all living organisms. They are transported in the environment, undergo transformations, biomagnify in food chains and are universally found in humans and animals. Understanding their fate in the envi-ronment and tracing them back to their sources is important, but difficult.

The insecticide DDT has effectively been used to combat malaria; however its extensive use in agri-culture led to severe ecotoxicological problems like egg-shell thinning in Baltic birds. Because of these deleterious effects DDT is classified as POP and the global use of DDT has been drastically reduced in the last decades. But DDT is still ubiquitous in nature and still threatens people’s health (Turosov et al., 2002). DDT is usually abundant in environmental samples in combination with structurally related compounds like DDD (Fig 1). DDD is a pollutant itself and can result as a by-product of the technical DDT synthesis or it can be formed by degradation of DDT in the environment.

We analyzed DDT and DDD samples to trace DDT dynamics in the environment and to demonstrate how stable heavy isotopes can be used as tracers of POP turnover.

Stable heavy isotopes are ever-present tracers: their natural abundances get modulated by physical and chemical isotope effects and therefore reflect synthesis and transformation pathways. Stable iso-tope abundances are conventionally measured as whole-molecule δ values, however, chemical reac-tions modulate isotope abundances of individual intramolecular positions (isotopomer abundances). We apply NMR spectroscopy to determine individual deuterium (D) isotopomer abundances of DDT and related compounds and we link these isotopomer abundances to synthesis and transformation processes of DDT.

Reference samples of DDT and DDD differ in their δD by up to 80 ‰ (Vetter et al., 2006) which indi-cates different sources for these compounds. However, by measuring individual D isotopomer abun-dances of both compounds we observed that the difference in the whole-molecule δD value is caused by only one intramolecular position (Fig 1), while common molecular parts do not differ. This leads to the conclusion that both compounds can have the same source. We trace the strong D enrichment of this individual DDD isotopomer back to the technical DDT synthesis and show how the isotopomer pattern of DDD formed by anaerobic degradation of DDT differs greatly from synthetic DDD. The D isotopomer patterns allow a clear distinction between these sources.

Tracing pollutant turnover by isotopomer analysis has the power to understand transformation pro-cesses, identify sources and polluters, and evaluate the effectiveness of remediation approaches.

Figure 1: Overlay of expansions of D NMR spectra of reference samples of o,p’-DDD and p,p’-DDT. The NMR signal intensity is proportional to the isotopomer abundance.

Anhang 1

83

P 41 Isotope Effects of Enzymatic Dioxygenation of Nitrobenzene and 2-Nitrotoluene by Nitrobenzene Dioxygenase

S. Pati1,2

, H.- P. Kohler1, J. Bolotin

1, R. Parales

3, T. Hofstetter

1,2

1Eawag, Dübendorf, Schweiz

2ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich, Schweiz

3University of California, Department of Microbiology, Davis, CA, Vereinigte Staaten von Amerika

Oxygenation of aromatic rings is a frequent initial step in the biodegradation of persistent contami-nants, and the accompanying isotope fractionation is increasingly used to assess the extent of trans-formation in the environment. Here, we systematically investigated the dioxygenation of two nitroaromatic compounds (nitrobenzene and 2-nitrotoluene) by nitrobenzene dioxygenase (NBDO) to obtain insights into the factors governing its C, H, and N isotope fractionation. Experiments were car-ried out at different levels of biological complexity from whole bacterial cells to pure enzyme. C, H, and N isotope enrichment factors and kinetic isotope effects (KIEs) were derived from the compound-specific isotope analysis of nitroarenes, whereas C isotope fractionation was also quantified in the ox-ygenated reaction products. Dioxygenation of nitrobenzene to catechol and 2-nitrotoluene to 3-methylcatechol showed large C isotope enrichment factors, εC, of −4.1 ± 0.2‰ and −2.5 ± 0.2‰, re-spectively, and was observed consistently in the substrates and dioxygenation products. εH- and εN-values were smaller, that is −5.7 ± 1.3‰ and −1.0 ± 0.3‰, respectively. C isotope fractionation was also identical in experiments with whole bacterial cells and pure enzymes. The corresponding

13C-

KIEs for the dioxygenation of nitrobenzene and 2-nitrotoluene were 1.025 ± 0.001 and 1.018 ± 0.001 and suggest a moderate substrate specificity. Our study illustrates that dioxygenation of nitroaromatic contaminants exhibits a large C isotope fractionation, which is not masked by substrate transport and uptake processes and larger than dioxygenation of other aromatic hydrocarbons.

84

P 42 Mechanistic insights into the anaerobic biodegradation of trichloroethene with dual element carbon and chlorine isotope analysis

A. Pérez-de-Mora1, L. Douglas

2, S. Cretnik

1, M. Höche

1, A. H. Meyer

1, O. Shouakar-Stash

3,

E. A. Edwards4, B. Sherwood-Lollar

2, M. Elsner

1

1Helmholtz Zentrum München, Institut für Grundwasserökologie, Neuherberg, Deutschland

2University of Toronto, Dept. of Earth Sciences, Toronto, Kanada

3University of Waterloo, Dept. of Earth Sciences, Waterloo, Kanada

4University of Toronto, Dept. of Chemical Engineering, Toronto, Kanada

Tricloroethene (TCE) is a toxic industrial solvent commonly found in contaminated groundwater. Here, the primary biotransformation mechanism for TCE is reductive dechlorination under anaerobic condi-tions, which involves the sequential replacement of Cl atoms with H atoms. Compound specific isotope analysis (CSIA) is an analytical method that measures the ratio of naturally occurring stable isotopes in specific compounds. CSIA can be used to quantify the in situ biodegradation of toxic chlorinated ethenes, such as TCE, in groundwater. Despite the importance of reductive dechlorination for biologi-cal treatment of TCE-contaminated groundwater, the underlying reaction mechanisms remain unclear. For instance, the magnitude of observed kinetic isotope effects for carbon has varied widely for differ-ent bacteria and enrichment cultures [1]. This variability could indicate different initial transition states within the reaction mechanism or masking of the observed carbon kinetic isotope effect due to addi-tional rate-limiting steps (e.g. substrate binding, mass transfer limitations) during the degradation of TCE. Isotopic-masking effects can be circumvented by simultaneously analyzing changes in isotope ratios for two elements in so-called dual plots, since the extent of such effects is generally similar for both elements and non-fractionating.

Here, we probe the details of the reductive dechlorination mechanism of TCE in anaerobic dechlorinating cultures grown in batch mode using dual element (Δδ13C/Δδ37Cl) isotope analysis.The slopes of dual element isotope plots remain largely constant even when masking suppresses observ-able kinetic isotope effects, so different slopes indicate a different initial transition state in the degrada-tion mechanism [2]. Changes in carbon and chlorine stable isotope ratios were monitored during TCE biodegradation by a highly enriched Geobacter lovleyi strain KB-1 culture and two mixed cultures dom-inated by Dehalococcoides mccartyi and Dehalogenimonas sp., respectively. These cultures had been amended and enriched for months with other chorinated ethenes/ethanes prior to incubation with TCE as follows: G. lovleyi with tetrachlorothene (PCE), the D. mccartyi enrichment with 1,2-dichloroethane (1,2-DCA) and the Dehalogenimonas enrichment with trans-dichloroethene (trans-DCE). Molecular analysis of the reductive dehalogenase genes present in these cultures (rdh genes) indicate that the dominant organisms bear different reductive dehalogenases that are responsible for the reductive dechlorination process. Dual isotope (Δδ13C/Δδ37Cl) plots showed similar slopes for the G. lovleyi- (3.0 ± 0.1, R2=1) and the D. mccartyi- (4.5 ± 0.9, R2=0.92) dominated cultures and a different slope for the Dehalogenimonas-dominated culture (9.9 ± 3.5, R2=0.82). The slopes for G. lovleyi and D. mccartyi are similar to those previously reported for G. lovleyi strain GT and Desulfitobacterium hafniense Y51, which have been related to a single electron transfer mechanism [3]. Results for the Dehalogenimonas enrichment suggest a potential novel biodegradation mechanism for TCE. Dual el-ement CSIA can be a powerful tool in elucidating biodegradation pathways.

[1] Cichocka et al. (2008) Chemosphere 71, 639.

[2] Elsner (2010) J. Environ. Monit. 12, 2005.

[3] Cretnik et al (2013) Environ. Sci. Technol. 47, 6855.

85

P 43 Substanz-spezifische Isotopenanalytik: neue Ansätze zur Beurteilung von Schadstoffen in der aquatischen Umwelt

A. Meyer1, S. Reinnicke

1, K. Schreglmann

1, S. Qiu

1, M. Maier

1, M. Elsner

1

1Helmholtz-Zentrum München, Umweltisotopenchemie, Neuherberg, Deutschland

Verschiedene biogeochemische Prozesse (Sorption, Transport und Abbau) beeinflussen das Verhal-ten von Schadstoffen in der Umwelt. Für eine bessere Beurteilung der dominierenden Vorgänge benö-tigt es neuer analytischer Ansätze. Die substanz-spezifische Isotopenanalytik ist in den letzten Jahren vielversprechend zur Anwendungen gekommen, um den Abbau von Grundwasserkontaminanten (BTEX, LCKWs) zu charakterisieren (Schmidt et al. 2004). Unser Ziel ist es gewesen, erstmals die substanz-spezifische Isotopenanalytik für die Analyse von umweltrelevanten Herbiziden zu etablieren, um Veränderungen in deren natürlichen Isotopenverhältnissen (

13C/

12C;

15N/

14N) analysieren zu kön-

nen. Diese Veränderungen ermöglichen es Abbauprozesse von Sorption- und Transportprozessen zu unterscheiden. Im Verlauf der letzten Jahre entwickelten wir sowohl neue analytische, als auch Anrei-cherungsmethoden für die gaschromatographischer Isotopenverhältnis-Massenspektrometrie (GC-IRMS) der Herbizide Atrazin (Meyer et al., 2008, Schreglmann et al. 2013), Isoproturon (Penning und Elsner, 2007), MCPA, Dichlobenil, Bentazon (Reinnicke et al., 2010) und Phenoxyessigsäuren (Maier et al., 2013). Mit Hilfe dieser Methoden ist es uns in batch-Experimenten gelungen abbaubedingte Veränderungen in den

13C/

12C und

15N/

14N Isotopenverhältnissen der Herbizide zu detektie-

ren(Reinnicke et al. 2011; Penning et al., 2010). Darüber hinaus, konnten wir im Fall von Atrazin zei-gen, dass verschiedene natürliche Abbauwege mit unterschiedlichen zweidimensionalen Isotopen-plots (d

13C/ d

15N) assoziiert sind (Meyer und Elsner, 2013).

In einer aktuelle Studie kombinierten wir enantioselektive Gaschromatographie-Isotopenverhältnis-Massenspektrometrie mit enantioselektiven Analysen von Phenoxyessigsäuren (Qiu et al., 2014). Ge-gensätzliche Ergebnisse in der Kohlenstoffisotopenfraktionierung und in der Selektivität der Enantiomere ermöglichte die Identifikation von „Flaschenhälsen“ im biologischen Abbau. Solche Fla-schenhälse können auftreten bei i) der Anlagerung und Freisetzung des Herbizides von Sorptionsplät-zen und Massentransfer in Lösung, ii) bei der Aufnahme in die Zelle und iii) während der enzymati-schen Reaktion. Im ersten Szenario erwartet man weder Isotopenfraktionierung noch Fraktionierung in den Enantiomeren der Phenoxyessigsäuren (Limitierung durch Massentransfer). Im zweiten Szenario wäre nur eine Selektivität in den Enantiomeren wahrscheinlich, da die Isotopenfraktionierung aufgrund des Membrantransportes (geschwindigkeitsbestimmender Schritt) „maskiert“ wäre. Im Fall der enzy-matischen Reaktion (drittes Szenario) sollte aufgrund ihres selektiven Verhaltens sowohl Isotopen- , als auch Enantiomerfraktionierung auftreten.

Literatur:

Maier, M.P., Qiu, S. and Elsner, M. (2013) Anal. Bioanal. Chem.405(9), 2825-2831. Meyer, A.H. and Elsner, M. (2013). Environ. Sci. Technol. 47(13), 6884-6891. Meyer, A.H., Penning, H., Lowag, H. and Elsner, M. (2008). Environ. Sci. Technol. 42(21), 7757-7763. Penning, H. and Elsner, M. (2007). Analytical Chemistry 79(21), 8399-8405. Qiu, S., Gözdereliler, E., Weyrauch, P., Lopez, E.C.M., Kohler, H.-P.E., Sørensen, S.R., Meckenstock, R.U. and Elsner, M. (2014). Environ. Sci. Technol. 48(10), 5501-5511. Reinnicke, S., Bernstein, A. and Elsner, M. (2010) Anal. Chem. 82(5), 2013-2019. Schmidt, T.C., Zwank, L., Elsner, M., Berg, M., Meckenstock, R.U. and Haderlein, S.B. (2004). Anal. Bioanal. Chem. 378(2), 283-300. Schreglmann, K., Hoeche, M., Steinbeiss, S., Reinnicke, S. and Elsner, M. (2013). Anal. Bioanal. Chem. 405(9), 2857-2867.

86

P 44 Einfluss von Umweltfaktoren auf die stabilen Isotope von Stickstoff und Sauerstoff in gelöstem Nitrat währen der Denitrifikation - Kohlenstoffquellen und Wasserisotopenaustausch

A. Wunderlich1, R. Meckenstock

2, F. Einsiedl

1

1Technische Universität München, Lehrstuhl für Hydrogeologie, München, Deutschland

2Helmholtz Zentrum München, IGÖ, Neuherberg, Deutschland

Stabile Isotope von Stickstoff und Sauerstoff in gelöstem Nitrat werden häufig zur Quellenbestimmung erhöhter Nitratkonzentrationen im Grundwasser herangezogen. Durch mikrobielle Denitrifikation wer-den die leichteren Isotope (

14N,

16O) aus dem Restnitrat entfernt und es reichern sich die schwereren

Isotope (15

N, 18

O) im Restnitrat isotopenchemisch an. Bisherige Studien zu den Anreicherungsfaktoren (ε) und der relativen Anreichung von δ

18O im Verhältnis zu δ

15N (Δδ

18O/Δδ

15N) während des

Nitratabbaus zeigen eine große Bandbreite an Ergebnissen. Dadurch wird eine Anwendung von Iso-topenanalysen in gelöstem Nitrat für die Quantifizierung des Nitratabbaus mit Hilfe der Rayleigh Glei-chung, sowie die Quellenbestimmung von teilweise mikrobiell abgebautem Nitrat erschwehrt.

In Mikrokosmenversuchen haben wir einige der möglichen Umwelteinflüsse auf die Isotopenfraktionie-rung bei der Denitrifikation untersucht. Unsere Ergebnisse zeigen eine Abhängigkeit der Anreiche-rungsfaktoren von der vorhandenen Kohlenstoffquelle. Im Besonderen sehen wir einen deutlichen Un-terschied zwischen komplexen Kohlenwasserstoffringen (Toluol, Benzoat) und einfachen Kohlenwas-serstoffen wie Acetat.

Wir haben Hypothesen zur Erklärung dieses Einflusses basierend auf einer Veränderung der relativen Prozesskinetiken des Nitrattransportes in die Zelle im Vergleich zur intrazellulären Nitratreduktion for-muliert. Diese postulieren eine Minderung des potentiellen Nitrattransportrates in die Zelle als Erklä-rung für unsere Beobachtungen.

Weiterhin untersuchten wir einen möglichen Einfluss der Isotopenkomposition von Wasser auf Nitratisotope durch eine partielle Umkehr der Nitratreduktionsreaktion. Ein solcher Einbau von Sauer-stoffatomen aus dem umgebenden Wasser würde die

18O-Isotopenwerte des gelösten Restnitrats be-

einflussen. Unsere Versuche ergaben, dass wenn nitrifizierende Bakterien mit dem NXR Enzym (Nitritoxidoreduktase) unter anaeroben Bedingungen Nitrat reduzieren ein solcher Isotopenaustausch stattfindet. In Reinkulturen von gewöhnlichen Denitrifizierern mit dem NaR Enzym (Nitratreduktase) findet jedoch kein Austausch statt. Der Einbau von Sauerstoffatomen aus Wasser in das verbleibende Nitrat kann durch die Reversibilität des NXR Enzyms erklärt werden und betrug in unseren zeitlich be-grenzen Inkubationen von natürlichen Sedimenten bis zu 5% des Sauerstoffs im verbliebenen gelös-ten Nitrat (Fig. 2). Dadurch verschiebt sich das Verhältnis Δδ

18O/Δδ

15N während der Denitrifikation

und können die in der Umwelt beobachteten variierenden Steigungen nun erklären.

87

Poster

Session 5 – Klimaänderungen und -rekonstruktionen

P 45 Stable hydrogen and carbon isotope ratios of methoxyl groups during plant litter decomposition

T. Anhäuser1, M. Greule

1, M. Zech

2,3, K. Kalbitz

4, F. Keppler

1

1Universität Heidelberg, Institut für Geowissenschaften, Heidelberg, Deutschland

2Universität Bayreuth, Geomorphologie, Bayreuth, Deutschland

3Universität Halle-Wittenberg, Biogeochemie, Halle, Deutschland

4Technische Universität Dresden, Soil Resources and Land Use, Dresden, Deutschland

Stable hydrogen and carbon isotope ratios of methoxyl groups (δDmethoxyl and δ13

Cmethoxyl values, re-spectively) in plant material were discovered to have characteristic signatures. These isotopic signa-tures can be used for a variety of applications such as constraining the geographical origin and au-thenticity of biomaterials [1-3]. Recently it has also been suggested that δDmethoxyl values of sedimen-tary organic matter of geological archives might serve as a palaeoclimate/-hydrology proxy [4]. How-ever, organic matter in geological archives is usually subject to both biotic and abiotic degradation processes and an evaluation of its potential impact on the δDmethoxyl and δ

13Cmethoxyl values would allow

more reliable interpretations of both isotopic signatures. Here we tested this potential influence exem-plarily by measuring δDmethoxyl and δ

13Cmethoxyl values from foliar litter of five different tree species (Syc-

amore maple, Mountain ash, European beech, Norway spruce and Scots pine) which were exposed to natural degradation in a field experiment. The samples were collected over a 27 months period and further parameters including the total mass loss as well as the degradation of lignin and cellulose were determined [5,6]. The δDmethoxyl values of all investigated litter species showed no significant temporal trend throughout the degradation experiment and fluctuations can be explained reasonably by consid-ering the analytical and internal precision of the applied method. Whilst δ

13Cmethoxyl values of two litter

species (Sycamore maple and European beech) showed also no obvious temporal trends, three litter species (Mountain ash, Scots pine and Norway spruce) became

13C enriched by about 4‰ on average

already after 9 month of degradation. These findings allow us a first estimation of the potential impact of degradation processes on δDmethoxyl and δ

13Cmethoxyl values of organic matter. We propose that

δDmethoxyl values of organic matter might be unaffected by degradation processes and have the poten-tial to be applied to a wide range of climate archives such as tree rings and sediments containing or-ganic matter. On the other hand care may have to be taken if δ

13Cmethoxyl values of degraded organic

matter are used for paleoclimate/-environmental investigations.

1. Keppler F, Harper DB, Kalin RM, Meier-Augenstein W, Farmer N, Davis S, Schmidt H-L, Brown DM, Hamilton JTG. Stable hydrogen isotope ratios of lignin methoxyl groups as a paleoclimate proxy and constraint of the geographical origin of wood. New Phytol. 2007 Jan;176:600-609.

2. Keppler F, Hamilton JTG. Tracing the geographical origin of early potato tubers using stable hydro-gen isotope ratios of methoxyl groups. Isotopes Environ. Health Stud. 2008 Dec;44:337-347.

3. Greule M, Tumino LD, Kronewald T, Hener U, Schleucher J, Mosandl A, Keppler F. Improved rapid authentication of vanillin using δ13C and δ2H values. Eur. Food Res. Technol. 2010 Aug;231:933-941.

4. Anhäuser T, Sirocko F, Greule M, Esper J, Keppler F. D/H ratios of methoxyl groups of the sedi-mentary organic matter of Lake Holzmaar (Eifel, Germany): A potential palaeoclimate/-hydrology proxy. Geochim. Cosmochim. Acta. Elsevier Ltd; 2014 Aug;(in press).

5. Don A, Kalbitz K. Amounts and degradability of dissolved organic carbon from foliar litter at different decomposition stages. Soil Biol. Biochem. 2005 Dec;37:2171-2179.

6. Kalbitz K, Kaiser K, Bargholz J, Dardenne P. Lignin degradation controls the production of dissolved organic matter in decomposing foliar litter. Eur. J. Soil Sci. 2006 Aug;57:504-516. .

88

P 46 Neue Ergebnisse zur Klimageschichte Ostafrikas anhand eines gekoppelten

2H-

18O Biomarker

Ansatzes

J. Hepp1,2

, R. Zech3, M. Tuthorn

1, B. Glaser

2, W. Zech

1, A. Hemp

4, M. Zech

1,2

1Universität Bayreuth, Lehrstuhl für Geomorphologie, Bayreuth, Deutschland

2Martin-Luther-Universität Halle-Wittenberg, Bodenbiogeochemie, Halle, Deutschland

3Universität Bern, Geographisches Institut, Bern, Schweiz

4Universität Bayreuth, Pflanzensystematik, Bayreuth, Deutschland

Die Stabilisotopie von Niederschlagswasser (δ2H und δ

18O) ist maßgeblich klimatisch gesteuert. Es

verwundert daher nicht, dass entsprechende Stabilisotopenanalysen zu einem der wichtigsten Werk-zeuge für die Rekonstruktion von Klimageschichte wurden. Um einen Beitrag zur Rekonstruktion der Klimageschichte Ostafrikas zu leisten, untersuchen wir eine 6.5 m mächtige Löß-Paläoboden-Sequenz im Maundi Krater (3°10‘27.5‘‘S, 37°31’05.8’’E) der an den Süd-Osthängen des Mt. Kilimand-scharo auf 2780 m ü. NN gelegen ist. Die Maundi-Sedimente in 3.15 m Tiefe datieren gemäß den

14C-

Datierungsergebnissen auf ca. 41 cal ka BP. Die Sedimentationsgeschichte begann jedoch vermutlich schon im frühen Jungpleistozän (ca. 100 ka BP), abgeleitet aus der linearen Extrapolation der

14C-

Datierungsergebnissen.

Unsere methodische Herangehensweise umfasst insbesondere substanzspezifische δ2H-Analysen

von Pflanzenwachs-bürtigen Alkanbiomarkern und substanzspezifische δ18

O-Analysen von Hemizellulose-bürtigen Zuckerbiomarkern. Dieser kombinierte

2H-

18O Biomarker Ansatz erlaubt es

zwischen dem Niederschlagssignal und der Blattwasseranreicherung (deuterium-excess des Blatt-wassers als Proxy für relative Luftfeuchte) zu unterscheiden (Zech et al., 2013. Chemical Geology). Die Berechnung der Isotopensignatur der Paleoniederschläge erfolgt hierbei über die lokale Evapora-tionslinie und deren Schnittpunkt mit der lokalen meteorischen Wasserlinie des Kilimanjaro Südhangs.

(Abbildung 1)

Die hier vorgestellten ersten vorläufigen Ergebnisse bestätigen das Vorherrschen humider Klimabe-dingungen während der „African Humid Period“ (AHP) und trockenerer Klimabedingungen während der Jüngeren Dryas (YD) und dem „Last Glacial Maximum“ (LGM). (Abbildung 1). Der rekonstruierte deuterium-excess des Blattwassers deutet zudem auf ein „megadrought“ (MD) Ereignis zwischen ca. 68 - 61 ka BP hin. Diese deuterium-excess Ergebnisse stehen jedoch interessanterweise nicht im Ein-klang mit den entsprechenden rekonstruierten Isotopenwerten des Niederschlagswassers sofern diese im Sinne des „amount effects“ interpretiert werden (Abbildung 1). Durch den Vergleich unserer rekon-struierter Blattwasser- und Niederschlagswerte mit bestehenden Isotopen-Klimakurven des Challa Sees, Tanganyika Sees und des Malawi Sees hoffen wir in Zukunft die Klimageschichte Ostafrikas sowie die verantwortlichen klimatischen Steuerungsmechanismen besser verstehen zu können.

Referenzen:

Zech, M., Tuthorn, M., Detsch, F., Rozanski, K., Zech, R., Zöller, L., Zech, W., Glaser, G. “A 220ka terrestrial δ

18O and deuterium excess biomarker record from an eolian permafrost paleosol sequence,

NE-Siberia”. Chemical Geology 360-361, 220-230

Abbildung 1: δ2H n-Alkane, δ

18O Zucker, deuterium-excess, und rekonstruierte NS-Werte für das ca.

100 ka zurückreichende Klimaarchiv des Maundi-Kraters am Kilimandscharo. MD = „megadrought“, LGM = „Last Glacial Maximum“, YD = Jüngere Dryas, AHP = „African Humid Period“. Anhang 1

89

P 47 Erste

18O Zuckerbiomarker-Ergebnisse von Spätglazialen und Frühholozänen Seesedimenten

des Gemündener Maars in der Eifel

T. Bromm1, F. Sirocko

2, B. Glaser

1, M. Zech

3,1

1Martin-Luther-Universität Halle-Wittenberg, Bodenbiogeochemie, Halle, Deutschland

2Universität Mainz, Institut für Geowissenschaften, Mainz, Deutschland

3Universität Bayreuth, Lehrstuhl für Geomorphologie, Bayreuth, Deutschland

Die Stabilisotopie von Niederschlagswasser und Seewasser (δ2H und δ

18O) ist maßgeblich klimatisch

gesteuert. Für die Rekonstruktion von Paläoklima werden daher u.a. 18

O-Isotopenanalysen von See-sedimenten durchgeführt. Um einen Beitrag zur Rekonstruktion der Klimageschichte Mitteleuropas und zu einem verbesserten Verständnis der Klimasteuernden Mechanismen zu leisten untersuchen wir die Spätglazialen und Frühholozänen Seesedimente des Gemündener Maars in der Eifel (Sirocko et al., 2013). Im Fokus unserer hier vorgestellten Untersuchungen stehen insbesondere Zuckerbio-marker und deren

18O-Isotopensignatur, die mittels einer Gaschromatographie-

18OPyrolyse-

Isotopenmassenspektrometrie (GC-18

OPy-IRMS) ermittelt wurde (Zech and Glaser, 2009)

Aufgrund der relativen Häufigkeit von Fucose im Verhältnis zu Arabinose und Xylose (fuc/(ara+xyl) > 0,4) kann von einem hauptsächlich aquatischen Ursprung der Zuckerbiomarker im Gemündener Maar ausgegangen werden (Zech et al., 2014). Die Zuckerbiomarker spiegeln daher im Wesentlichen die 18

O-Isotopie des Seewassers des Gemündener Maars wider. Sowohl Arabinose, Fucose als auch Xy-lose weisen die gleichen

18O-Trends auf und zeigen im Frühholozän deutlich positivere Werte (35 bis

40‰) als in der Jüngeren Dryas mit einem markanten Shift von über 5‰ während des Übergangs (Abbildung 1). Leicht positivere Werte (2-3‰) charakterisieren des Weiteren die Sedimente des Böl-ling/Alleröds.

Abbildung 1

Damit entspricht der Verlauf der hier anhand von Zuckerbiomarkern aufgestellten 18

O Klimakurve in etwa dem Verlauf der

18O Klimakurven Grönländischer Eisbohrkerne. Dies spiegelt die dominante

Steuerung des Mitteleuropäischen Klimas durch den Nordatlantik wider und lässt vermuten, dass die 18

O Klimakurve der Seesedimente des Gemündener Maars zumindest teilweise im Sinne von Tempe-raturschwankungen interpretiert werden kann. Ob darüber hinaus auch eine Anreicherung des Seewasssers durch Verdunstung die hier aufgestellt

18O-Klimakurve beeinflusst hat, wird derzeit im

Rahmen von δ2H Analysen an Alkanen und einem gekoppelten

2H-

18O Ansatz untersucht.

Referenz

Sirocko F., Dietrich S., Veres D., Grootes P., Schaber-Mohr K., Seelos K., Nadeau M.-J., Kromer B., Rothacker L., Röhner M., Krbetschek M., Appleby P., Hambach U., Rolf C., Sudo M., and Grim S. (2013) Multi-proxy dating of Holocene maar lakes and Pleistocene dry maar sediments in the Eifel, Germany. Quaternary Science Reviews 62, 56-76.

Zech M and Glaser B (2009) Compound-specific δ18

O analyses of neutral sugars in soils using GC-Py-IRMS: problems, possible solutions and a first application. Rapid Communications in Mass Spec-trometry 23, 3522-3532.

Zech, M., Tuthorn, M., Zech, R., Schluetz, F., Zech, W., Glaser, B., 2014. A 16-ka δ18

O record of la-custrine sugar biomarkers from the High Himalaya reflects Indian Summer Monsoon variability. Jour-nal of Paleolimnology 51, 241-251.

Abbildung 1: Gesamtkohlenstoffkurve der Gemündener Maar Seesedimente von 6 bis 7,7 m Bohr-kerntiefe und δ

18O Klimakurven der Zuckerbiomarker Arabinose, Fucose und Xylose.

90

Anhang 1

91

Poster

Session 6 – Ökosysteme

P 48 Improved calculation of N2 and N2O fluxes from

15N-labelled NO3

- in soil for combined

15N

analysis of N2, N2+N2O and N2O in gas samples

R. Well1, W. Eschenbach

1, A. Gattinger

2, H.- M. Krause

2, D. Lewicka-Szczebak

1

1Thünen Institut, Agrarklimaschutz, Braunschweig, Deutschland

2Forschungsinstitut für biologischen Landbau, Frick, Schweiz

Dinitrogen (N2) and nitrous oxide (N2O) fluxes from denitrification in soil can be quantified using the 15

N tracer technique. This includes

15N labelling of nitrate (NO3

-) in soil and subsequent isotope analysis of

gas samples from enclosures, i.e. mixtures of soil-derived and atmospheric N2 and N2O. Measuring pool-derived N2 or N2O has been shown to include two calculation problems, (i) arising from multiple pools (Mulvaney, 1988, Arah , 1992) and (ii) dealing with the non-random distribution of N2 and N2O mole masses (Hauck et al., 1958). Non-randomness can be solved in case of two distinct pools (i.e. soil and atmosphere) if m/z 28, 29 and 30 are correctly analysed and the

15N enrichment of one pool is

known (). In case of three pools, it can also be solved if the N enrichment of two pools is known (Spott & Stange, 2008). Moreover, NO3

- pools generating N2 and N2O can be identical or different, e.g. if N2O

evolved from higher enriched NO3- in deeper soil was more reduced to N2 compared to N2O evolved

from N2O from shallow soil with lower enrichment, or vice versa.

Taking these effects into account and, using the additional information from the sequential measure-ment of

15N isotope signatures of N2 , N2O and N2+N2O (Lewicka-Szczebak et al., 2013), we propose

some improved routines for data analysis. Model calculations are conducted to illustrate potential er-rors and deviations between previous and improved calculations. Finally a laboratory data set is ana-lysed to illustrate the potential progress in process identification when using improved calculations.

References:

Arah, J.R.M., New formulae for mass spectrometric analysis of nitrous oxide and dinitrogen emissions, Soil Sci. Soc. Am. J. 56, 795 - 800, 1992.

Hauck, R.D., S.W. Melsted, and P.E. Yannkwich, Use of N - Isotope distribution in nitrogen gas in the study of denitrification, Soil Science 86, 287 - 291, 1958.

Lewicka-Szczebak, D., Well, R., Giesemann, A., Rohe, L., Wolf, U. (2013): An enhanced technique for automated determination of

15N signatures of N2, (N2+N2O) and N2O in gas samples. Rapid communi-

cations in mass spectrometry, 27 1548-1558.

Mulvaney, R.L.. 1984. Determination of 15

N-labelled dinitrogen and nitrous oxide with triple collector mass spectrometer. Soil Sci. Soc. Am. J. 48:690 - 692.

Mulvaney, R. L. and R. M. vanden Heuvel (1988). "Evaluation of nitrogen-15 tracer techniques for di-rect measurement of denitrification in soil: IV. field studies." Soil Science Society of America Journal 52: 1332-1337.

Spott, O., et al. (2006). "A 15

N-aided artificial atmosphere gas flow technique for online determination of soil N2 release using the zeolite Köstrolith SX6â." Rapid Communications in Mass Spectrometry 20: 3267-3274.

Spott, O. and C. F. Stange (2007). "A new mathematical approach for calculating the contribution of anammox, denitrification and atmosphere to an N2 mixture based on a

15N tracer technique." Rapid

Communications in Mass Spectrometry 21: 2398-2406.

92

P 49 The stable isotope and elemental response of Fucus vesiculosus on acidification, warming and eutrophication in mesocosm studies (Kiel, Sylt)

V. Winde1, A. Pansch

2, B. Al-Janabi

3, S. Sokol

3, B. Buchholz

3, M. Voss

1, B. Schneider

1, M. Wahl

3,

R. Asmus2, H. Asmus

2, M. E. Böttcher

1

1Institut für Ostseeforschung Warnemünde, Marine Geologie, Rostock, Deutschland

2AWI Sylt, List (Sylt), Deutschland

3GEOMAR, Kiel, Deutschland

In the frame of the German BIOACID II project the separate and combined effects of different stress factors (acidification, warming, eutrophication) on the elemental and stable isotope composition of Fucus vesiculosus are investigated by means of benthic mesocosm experiments in coastal waters of the Baltic and the North Sea. We aim for a calibration of the geochemical and stable isotope composi-tion of Fucus in response to single and combined temperature, pCO2 (pH), and nutrient changes.

Benthocosm experiments are carried out in the Kiel Fjord and at the waddenSeastation of the AWI in List (Sylt) with a fully crossed array of 2 stressors: an increase in temperature and an increase in at-mospheric CO2 partial pressure. The experiments run for almost 3 months per season. Additionally, in summer an experiment with a parallel combination of elevated CO2 and temperature with and without elevated nutrients were carried out. On both a regular (weekly) and high resolution (24H-cycle) base, the aquatic chemistry (e.g. TA, pH, δ

13C(DIC)) as well as the composition of the grown Fucus

vesiculosus organic tissue (e.g. CNSP, C, N, and S stable isotope ratios) are followed. In the 24h-cycles the community response to diurnal light cycles was followed in high time resolution.

It was found, that seasonal variations in the composition of the input solutions (brackish water from the Kiel Fjord or North Sea) were reflected by changes in the experiments with short time delay. The changes in the aquatic chemistry of the mesocosms, however, were strongly superimposed for most parameters during daytime by biological activity (photosynthesis, respiration). The biological activity during the 24h-campaigns, alternating phases of net respiration and photosynthesis, was creating strong variations in the dissolved carbonate system and significant changes in the carbon isotope composition of DIC. The atmosphere of some experimental set-ups was enriched with isotopically light gaseous carbon dioxide. This caused fast corresponding changes in the isotopic composition of DIC, thereby acting as a tracer for newly formed organic tissue and carbonates. The chemical and isotopic parameters of the dissolved carbonate system showed differences between the set ups. The organic tissue of Fucus vesiculosus shows seasonal variability in the C, N, S contents and the isotopic compo-sition.

93

P 50 Variations of stable isotope signatures and element stoichiometry of Fucus vesiculosus under anthropogenic impact in the Kiel Bight, Baltic Sea

V. Winde1, A. Mahler

1, M. Voss

1, M. E. Böttcher

1

1Institut für Ostseeforschung Warnemünde, Marine Geologie, Rostock, Deutschland

In the frame of the BMBF project BIOACID II we aim for an understanding of the natural distribution and variation of isotopic and element composition (e.g. CNSP) in Fucus vesiculosus growing around the coast line of the Kiel Fjord (part of the Baltic Sea). Also the environmental conditions (aquatic chemistry, temperature, salinity) are important for the Fucus composition. Some changes in aquatic chemistry are related to stress factors like human activity (e.g. waste input) and further factors leading to specific changes in the composition of Fucus vesiculosus.

On different Station at the west and east coast of the Kiel Fjord three size classes (small, medium, large) of Fucus vesiuculosus and there habitat (water sample) were sampled. For each sampling sta-tion the composition of the Fucus vesiculosus organic tissues (stoichiometry and stable isotope com-position of carbon, nitrogen, sulphur) as well as the aquatic chemistry (TA, pH, salinity, δ

13C(DIC),

main and trace elements and nutrients) are analysed.

It is shown, that Fucus vesiculosus indicates clear differences in the N contents and stable isotopes between the west and the east site of the Kiel Fjord. Stable nitrogen isotope signatures in Fucus vesiculosus, are useful proxies to identify the influence factors in the Fucus habitat. From the data it is obtained that the influence of human activity (wastewater treatment plant, harbour), small streams and drainage channels, which flow from the near coastal area into the bight, leads to different Fucus vesiculosus compositions. In future work, it is intended to extend the investigation to trace element signatures to further estimate environmental impacts.

94

P 51 Tracing nutrient flows from offshore aquaculture - possible application for SIA?

Y. Rößner1, N. Hillgruber

1, H. Kusche

1, U. Focken

1

1Thuenen Institute of Fisheries Ecology, Ahrensburg Branch, Ahrensburg, Deutschland

An increasing demand for seafood in a situation of declining fish landings made aquaculture the fast-est growing food production sector in recent years. The resulting conflict of interests for space in coastal areas (e.g., traffic, tourism, nature conservation) forces future aquaculture operations to move further offshore. However, moving aquaculture endeavors into offshore waters is met by a number of new challenges that are currently the focus of intense research activities. For example, rough offshore conditions with high dilution potential and deeper water depths complicate the retraceability of any aq-uaculture impacts on the environment, most importantly nutrient emissions. However, since the EU Marine Strategy Framework Directive and other international agreements explicitly demand the study of potential effects, methods need to be developed to trace potential emissions from aquaculture op-erations.

Stable isotopes (i.e., δ13

C and δ15

N) can be measured in small concentrations and therefore lend themselves to tracing nutrients associated with fish production through the food chain, even in rough, offshore environments. As part of the project “Offshore site selection for a sustainable and multi-functional use of marine areas in heavily utilized seas with the North Sea as an example” we will ex-amine the potential of stable isotope patterns as tracers for fish production in offshore waters.

Since the nutritional impact from fish production is likely to predominantly affect benthic organisms, brittle stars (Ophiura ophiura and O. albida) were identified as potential indicator species for anthropo-genic nutrient enrichment because they are opportunistic feeders and therefore likely to incorporate any available organic matter, are widely distributed in the area and can typically be sampled through-out the year in quantities sufficient for analysis.

To date, stable isotope analysis (SIA) has been conducted on brittle stars from a potential offshore aquaculture site in the German North Sea to define a baseline, i.e., the natural isotopic pattern. In ad-dition, stable isotope patterns of potential fish feed ingredients were analyzed and tested during an 8-week feeding trial to determine the best SI signal from fish production. All samples have been defatted prior to EA-IRMS.

Figure 1

Plant protein sources in fish feed like soy and wheat gluten differ substancially from the marine back-ground, thus indicating that these compounds will likely lend themselves to providing a stable isotope signal clearly different from the baseline of the benthic indicator species. But also the commercial feed shows a large distance from marine sources, indicating a heavy use of terrestrial proteins.

Thus, our data suggest that plant protein sources in fish feed may help to identify and trace nutrient emissions from aquaculture in offshore waters of the North Sea.

This study has been partly funded by Bundesanstalt für Landwirtschaft und Ernährung (BLE), upon a decision of Deutscher Bundestag.

95

Anhang 1

96

P 52 Effect of light exclusion on

13CO2 efflux from branches of European beech in late winter

E. A. Ribeiro Valim1, R. Matyssek

1, T. Grams

1

1Technische Universität München Wissenschaftszentrum Weihenstephan, Depatment für Ökologie

Lehrtuhl für Ökophysiologie der Pflanzen, Freising, Deutschland

In woody trees, branch internal CO2 is expected to be re-assimilate by bark photosynthetic whenever sufficient light for such activity is present (Cernusak et al. 2001). As the CO2-fixing enzym Rubisco discriminates against

13CO2 by about 29‰ (Raven & Farquhar, 1990),

13CO2 should accumulate in the

bark cortex, increasing the δ13

C of the CO2 difusing out of the branches. This contribution tests this hypothesis in branches of adult European beech trees during the winter months before the leaf flush.

To this end, we measured the carbon isotopic composition of CO2 respired by branch sections of six adult F. sylvatica individuals. On each tree, one transparent and one darkened branch chamber (cov-ered with aluminum foil) was installed. After a period of 20 to 30 days, CO2 was sampled after flushing the chambers with CO2-free air (Damesin et al. 2005). Sampling was done during day and night in or-der to evaluate the diurnal pattern of

13CO2 efflux from dark and sunlight exposed branches. In addi-

tion and to verify the influence of the darkened chamber, 13

CO2 efflux was assessed 4 and 24 hours as well as 8 and 20 days after the removal of the aluminum foil. CO2 refixation by bark photosynthetic re-sulted in significantly different values between darkened and sunlight exposed beech branches (t(8,4) = 2,553; p = 0,033) with average values of the sampled CO2 of -26,5 ± 1,9 ‰ and -22,9 ± 3,0 ‰, respec-tively. In contract to the darkened chambers, uncovered branches displayed a diurnal pattern (F4, 62= 4, 9, p= 0,001). The highest δ

13C for uncovered branches were sampled during the afternoon and

ranged between -22,0 and -23,1 ‰, while the lowest values was -29,83 ‰ measured at midnight. Four hours after the removal of the aluminum foil, the δ

13C of the CO2 efflux from branches displayed and

increase by 2,4 ‰. In the subsequent 20 days after the foil removal, this value did not change significnatly (F(3,15) = 2,151; p >0,29).

Our results give evidence for a strong influence of Rubisco discrimination on the δ13

C of CO2 diffusing out of the branches by directly affecting the branch-internal CO2. Thus, the lowest observed δ

13C in

darkened branches and during the night might be explained by the absence of Rubisco activity under these conditions. On the other hand, in sun-exposed branches, parts of branch-internal CO2 may be refixed by Rubisco, increasing both the

13δC of the branch-internal CO2 and thus of the CO2 defusing

out of the branch.

References

Cernusak, L. A., Marshall, J. D., Comstock, J. P., & Balster, N. J. (2001). Carbon isotope discrimina-tion in photosynthetic bark. Oecologia, 128(1), 24-35.

Damesin, C., Barbaroux, C., Berveiller, D., Lelarge, C., Chaves, M., Maguas, C., ... & Pontailler, J. Y. (2005). The carbon isotope composition of CO2 respired by trunks: comparison of four sampling methods. Rapid communications in mass spectrometry, 19(3), 369-374.

Raven, J. A., & Farquhar, G. D. (1990). The influence of N metabolism and organic acid synthesis on the natural abundance of isotopes of carbon in plants. New Phytologist, 116(3), 505-529.

97

P 53 Soil microbial C and N turnover under Cupressus lusitanica and natural forests in southern Ethiopia assessed by decomposition of

13C- and

15N-labelled litter under field conditions

M. Benesch1, B. Glaser

1, M. Dippold

2, W. Zech

3

1Martin-Luther- University Halle-Wittenberg, Soil Biogeochemistry, Halle, Deutschland

2Georg-August-University of Göttingen, Department of Agricultural Soil Science, Göttingen,

Deutschland 3University of Bayreuth, Soil Science and Soil Geography, Bayreuth, Deutschland

In the Munessa forest south of Addis Ababa (Ethiopia), increased demand of wood leads to a wide-spread deforestation strongly reducing species-rich natural forests dominated by Croton macrostachys, Podocarpus falcatus and Prunus africana. Parts of the deforested land have been re-forested with exotic tree species such as Cupressus lusitanica, but little is known about consequences of this land use change for soil C and N dynamics. Therefore, the question arises whether silvicultural management practices of differently aged Cupressus plantations influence soil microbial C and N turn-over under the sub-humid site conditions of the Munessa forest.

The objectives of the study were: (i) quantification of microbial litter-derived C and N incorporation un-der field conditions, (ii) identification of forest management effects on microbial litter-derived C and N incorporation (tree species effects: natural forest vs. Cupressus plantation with no management, thinning effects: Cupressus plantation with no management vs. Intense Promotion vs. Conversion, age class effects: Cupressus age class I vs. age class III) and (iii) elucidation of soil moisture ef-fects (dry soil conditions vs. wet soil conditions) on microbial litter-derived C and N utilization. To ad-dress these objectives, a labelling experiment with

13C- and

15N-enriched litter was installed and litter

degradation was studied over 2 years. Chloroform fumigation extraction allowed the quantification of microbial C and N storage (CSMB and NSMB) and the analysis of litter-derived tracer

13C and

15N incor-

poration into SMB.

Most of the 13

C and 15

N Tracer remained in the litter or was incorporated into bulk soil, whereas soil microbial biomass (SMB) showed minor incorporation. Microbial incorporation of litter-derived N was not significantly affected by the investigated variables over the whole experimental period. However, microbial litter-derived

13C utilization was higher under natural forest during dry soil conditions, where-

as Cupressus litter was less utilized by SMB. Wet soil conditions improved microbial litter-derived C utilization under Cupressus. Within the plantation plots, thinning led to increased microbial litter-derived C incorporation during dry soil conditions but heavy rains during wet phases resulted in anoxic conditions, inhibiting SMB. The intensity of thinning (Intense Promotion vs. Conversion) did not show any significant effect on litter-derived microbial C incorporation. Furthermore, our experiment con-firmed that in the Munessa ecosystem, soil humidity is the main influencing factor, resulting in signifi-cantly different nutrient turnover during dry and wet soil conditions. Our findings suggest that fast growing tree plantations established on Mollic Nitisols in the Munessa forest not necessarily contribute to a decline of soil sustainability with respect to short-term (microbial) C and N turnover.

98

P 54 C and N stable isotopes as possible indicators of food-web changes related to river restoration

B. Kupilas1, M. Schulte

2, D. Hering

1, T. Schmidt

2

1Universität Duisburg-Essen, Fakultät für Biologie, Aquatische Ökologie, Essen, Deutschland

2Universität Duisburg-Essen, Fakultät für Chemie, Instrumentelle Analytische Chemie, Essen,

Deutschland

Since “you are what you eat (plus a few ‰)” (DeNiro & Epstein 1976), many ecological studies nowa-days use stabele isotopes of carbon and nitrogen to investigate the resource base, to establish feed-ing links between organisms and to construct food webs. In this study, carried out within the EU-funded project REFORM (Restoring rivers FOR effective catchment Management, http://reformrivers.eu/), we applied stable isotope analysis of C and N in context of river restoration to quantitatively characterize patterns in trophic structure. We sampled different components of food webs on paired restored and non-restored reaches of rivers in 20 different catchments throughout Eu-rope. Amongst others, the sampling contained elements of the resource base (particulate organic mat-ter, aquatic and riparian plant material, periphyton) and macroinvertebrates comprising the major taxa within different functional feeding groups. Based on δ

13C and δ

15N-ratios we then (pairwise) compared

(1) the total extent of the community members in δ13

C - δ15

N bi-plot-space representing the total extent of trophic diversity within a food web, (2) the C- range characterizing the diversity of sources and (3) the N-range identifying the trophic length. In most cases restoration increased the diversity of sources as indicated by higher ranges in macroinvertebrates δ

13C. Here, methods and first results of this study

are presented.

DeNiro, M.J. & Epstein, S. (1976) You are what you eta (plus a few ‰): the carbon isotope cycle in food chains. Geol. Soc. Am. Abs. Prog. 8, 834-835

X

Index der Autoren

A Al-Janabi, B. P 49 Al-Raei, A. M. V 7 Al-Saud, M. P 25 Alexandra, N. V 5 Althoff, F. V 16 Anderson, T.-H. V 22 Anhäuser, T. P 45 Arend, M. P 32 Asmus, H. P 49 Asmus, R. P 49 Auerswald, K. P 33 Augusti, A. V 35 Augustin, J. V 3

B Bakkour, R. V 6 Banning, H. V 5 Barth, J. P 17 Barthel, M. V 14 Baumann, P. P 11 Baume, N. P 26 Benesch, M. P 53 Bensch, H. K. V. P 38 Benzing, K. V 16 Betson, T. V 35, P 40 Beyer, M. V 8, V 9, P 13 Bidartondo, M. I. V 34 Bol, R. P 14 Bolotin, J. V 24, P 41 Bonifacie, M. P 12 Boyd, D. V 16 Braker, G. V 22 Brand, W. V 21, P 3 Braun, A. P 33 Brendel, R. V 5 Breuer, L . P 20 Bromm, T. P 47 Brüggemann, N. P 8 Buchen, C. P 37 Buchholz, B. P 49 Buchmann, N. V 14 Buegger, F. P 7 Burghardt, D. P 11 Burkart, S. P 4 Bögelein, R. P 36 Böning, P. V 7 Böttcher, E. O. P 15 Böttcher, M. E. P 15, P 16, P 49, P 50, V 7, P 5 Böttcher, T. M. P 15

C Canonica, S. P 39 Casciotti, K. P 8 Cerli, C. V 4 Comba, P. V 16 Conrad, A. P 5 Correia, A. V 37 Costa e Silva, F. V 37 Cretnik, S. P 42 Cuntz, M. V 37

D Dahlenburg, R. V 26 Deerberg, M. V 1 Dellwig, O. P 16 Dippold, M. P 53 Doucett, R. R. P 8 Douglas, L. P 42 Dubbert, M. V 37 Dunsbach, R. V 4

Dybala-Defratyka, A. P 38 Dyckmans, J. V 2, P 8 Dücking, M. V 19

E Edwards, E. A. P 42 Ehlers, I. V 24, V 35, P 40 Eiche, E. V 5 Einsiedl, F. P 44 Eisenmann, H. V 25, P 12 Eisenreich, W. V 12 El-Matbouli, M. P 29 Elsner, M. P 2, P 38, P 7, P 42, P 43 Emmenegger, L. V 18, P 9 Eritt, M. P 3 Eschenbach, W. P 48, P 1 Escher, P. P 16, V 7

F Federherr, E. V 4 Feldermann, A. V 28 Fiebig, J. P 5 Fischer, A. V 25 Fischer, M. P 6 Flenker, U. V 15, P 31, V 20 Flessa, H. V 22, P 37 Focken, U. P 29, P 51 Forbes, M. P 8 Frede, H.-G. P 20 Fußhöller, G. P 31

G Gaj, M. V 8, V 9, P 13 Gangi, L . P 14 Gassen, N. P 23 Gattinger, A. P 48 Gebauer, G. V 34 Gebhardt, T. V 11 Geppert, U. P 32 Geßler, A. V 33 Giesemann, A. P 1, V 22, P 4, P 37, V 3, P 8 Gilbert, A. V 17 Gilevska, T. P 12 Glaser, B. P 53, P 46, P 47, P 35 Gleixner, G. V 29 Gougoulidis, V. V 15, P 31 Gralher, B. P 21 Grams, T. P 52, V 28, V 11 Grams, T. E. P 30 Greiner, S. V 16 Greule, M. V 23, P 45 Grzybkowska, A. P 38 Gute, E. P 9

H Haenelt, N. V 15, P 31 Hafner, B. P 30 Hamilton, J. T. V 23 Hamutoko, J. V 8, V 9 Hamutoko, Y. P 13 Harper, D. B. V 23 Harris, E. V 18, P 9 Hemp, A. V 29, P 46 Hepp, J. P 46, V 30 Herbstritt, B. P 22 Hering, D. P 54 Herrero-Martin, S. V 25 Hilkert, A . V 1, P 14

XI

Index der Autoren

Hillgruber, N. P 51 Himmelsbach, T. P 23, V 8, V 9, P 13 Hofstetter, T. V 24, P 39, V 6, P 41 Holdermann, T. V 26, V 19 Häberle, K.-H. P 30 Höche, M. P 42 Hülsemann, F. V 15, V 20

I Ivdra, N. V 25, P 12

J Janoschka, A. P 3 Jardin, K. V 13 Jochmann, M. A. P 2, P 10 Joss, A. V 18 Jost, H. P 14

K Kaiser, J . P 8 Kalbitz, K. V 4, P 45 Kammann, C. V 36 Kayler, Z. V 33 Kazimierz, R. V 29 Kemnade, C. V 34 Keppler, F. V 16, V 23, P 45 Kerner, R. P 32 Kipf, M. V 18 Knoeller, K. P 7 Knöller, K. V 10, P 18 Koeniger, P. P 23, V 8, V 9 Kohler, H.-P. P 41 Kolb, A. P 17 Kracht, O. P 14 Kraft, P. P 20 Krause, H.-M. P 48 Krieg, R. V 10 Kuells, C. P 13 Kujawinski, D. M. P 10 Kupilas, B. P 54 Kupka, H. J. V 4 Kusche, H. P 51 Königer, P. P 13

L Lange, L. V 4 Langel, R. V 2 Lehmann, M. M. P 6, V 14 Lehn, C. V 20 Leiber-Sauheitl, K. P 4 Lenhart, K. V 16, V 36 Lewicka-Szczebak, D., P 48, V 22, V 2, P 37, V 3 Liang, M.-C. P 8 Liebezeit, G. V 7 Limprecht, M. P 22 Lin, C.-T. P 8 Lipka, M P 15, P 16 Lohe, C. V 8 Löffler, N. P 5

M Macha, A. V 15, P 31 Magin, S. V 11 Mahler, A. P 50 Maier, M. P 43 Matyssek, R. P 52, P 30, V 28, V 11 Mayrhofer, R. P 29 McNeill, K. P 39 McRoberts, C. V 16 Meckenstock, R. P 44

Meier, C. P 24 Meijer, H. P 14 Merz, R. V 10 Meyer, A. P 43 Meyer, A. H. P 42 Michelsen, N. P 25 Mogusu, E. P 2 Mohn, J. V 18, P 8, P 9 Munch, J.-C. P 32 Mügler, I. V 30 Müller, C. V 10, V 36 Müller, D. P 31

N Neumann, T. V 5 Nick, P. V 5 Nilsson, M. V 35 Nimmanwudipong, T., V 17 Nitzsche, K. V 33

O Orlowski, N. P 20 Osenbrück, K. P 24 Ostrom, N. E. P 8 Ott, U. V 23

P Panetta, R. V 4 Pansch, A. P 49 Parales, R. P 41 Parr, M. K. V 15, P 31 Parra Suarez, S. P 19 Pati, S. P 41 Pereira, J. V 37 Piayda, A. V 37 Piper, T. P 26, P 27, V 20 Premke, K. V 33 Pritsch, K. P 32 Pucher, J. P 29 Pérez-de-Mora, A. P 42

Q Qiu, S. P 43

R Radke, J. P 14 Ratti, M. P 39 Rausch, R. P 25 Reinnicke, S. P 43 Reshid, M. P 25 Ribeiro Valim, E. A. P 52 Richnow, H.-H. V 25, P 12 Ridley, A. R. P 8 Riemann, M. V 5 Riemann, P. V 15, P 31 Rodchenkov, G. P 26 Rohe, L. V 22 Rutz, T. P 5 Ryabenko, E. P 7 Rzesanke, D. P 3 Rößner, Y. P 51

S Sachse, D. V 31 Sattler, T. V 23 Saugy, M. P 26 Saurer, M. P 6, V 27 Scheid, N. V 19 Schiebold, J. V 34 Schleucher, J. V 24, V 35, P 40

XII

Index der Autoren Schlueter, H.-J. V 1, P 14 Schlütz, F. V 30 Schmidt, T. V 4, P 54 Schmidt, T. C. P 10 Schmiedinger, I. P 15, P 16, V 7 Schneider, B. P 49, V 7 Schneiders, S. V 26, V 20, V 19 Scholübbers, D. P 28 Schreglmann, K. P 43 Schulte, M. P 54 Schulz, S. P 25 Schwieters, J. V 1 Schänzer, W. V 20, P 26, P 27, V 15, P 31 Schöler, H. V 23 Schönberg, R. V 5 Seffernick, J. L. P 38 Seitz, H.-M. P 24 Sherwood-Lollar, B. P 42 Shouakar-Stash, O. P 42 Siebert, C. P 25 Siegrist, H. V 18 Siegwolf, R. T. V 27, V 14, P 6 Sirocko, F. P 47 Sobolevsky, T. P 26 Sokol, S. P 49 Spahr, S. V 24 Stange, F. P 1 Steiker, A. E. P 8 Stelling, M. V 5 Stoeckl, L. P 23 Stoewer, M. P 18, P 7 Struck, U. P 16 Stumpp, C. P 18, P 21 Subah, A. P 23 Szwec, L. V 2, P 8 Sültenfuß, J. P 16

T Thevis, M. P 26, P 27 Thomas, A. P 26, P 27 Thomas, F. M. P 36 Tomasella, M. P 30 Toyoda, S. P 8 Tuthorn, M. P 46, V 30 Tuzson, B. P 9 Tütken, T. P 5

V van Geldern, R. P 17

van Leeuwen, C. P 14 Vetter, W. P 40 Vikari, A. P 33 Volders, F. V 4 von Gunten, U. V 24 von Holstein, I. V 32 Voss, M. P 49, P 50

W Wacker, U. P 5 Wackett, L. P. P 38 Wahl, M. P 49 Wanke, H. V 8, V 9, P 13 Wapelhorst, E. P 14 Wegener, F. V 14, P 34, V 13 Weiler, M. P 22 Weis, P. V 19 Weise, S. M. P 24 Well, R. P 48, P 1, V 22, P 4, V 2, P 37, V 3, P 8 Werner, C. V 37, V 14, P 34, V 13 Werner, K. P 35 Werner, R. A. V 14 Werner, W. P 36 Wigger, M. P 28 Winde, V. P 15, P 16, P 49, P 50, V 7 Windisch, W. P 33 Wissel, H. P 8 Wolbert, B. P 2 Wolbert, J.-B. P 10 Wolf, B. V 18, P 8 Wrage-Mönnig, N. V 22 Wu, Z. P 16 Wunderlich, A. P 44 Wunderlin, P. V 18 Wutzke, K.-D. P 28

X Xanke, J. P 23

Y Yamada, K. V 17 Yarnes, C. T. P 8 Yoshida, N. P 8, V 17

Z Zech, M. P 6, P 45, V 29, P 46, V 30, P 47, P 35 Zech, R. V 29, P 46, V 30 Zech, W. P 53, V 29, P 46, V 30

XIII

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XIV

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XVI

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XVII

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Arbeitsgemeinschaft Stabile Isotope e. V.German Association for Stable Isotope Researchwww.gasir.de

Jahrestagung 15. – 17. Oktober 2014 im Helmholz Zentrum, München, Germany